MASARYKOVA UNIVERZITA PEDAGOGICKÁ FAKULTA Katedra fyziky, chemie a odborného vzdělávání
Angličtina pro učitele fyziky Diplomová práce
Brno 2016
Autor práce: Bc. Pavel Jureček Vedoucí práce: Mgr. Lukáš Pawera
Bibliografický záznam JUREČEK, Pavel. Angličtina pro učitele fyziky: diplomová práce. Brno: Masarykova univerzita, Fakulta pedagogická, Katedra fyziky, chemie a odborného vzdělávání, 2016. 163 l., 3 l. příl. Vedoucí diplomové práce Mgr. Lukáš Pawera
Abstrakt Přestože je v dnešní době angličtina celosvětově hlavním dorozumívacím jazykem, je úroveň angličtiny studentů učitelství přírodovědných oborů na PdF MU v Brně v průměru velmi nízká. Situace je ještě horší, pokud se zaměříme na znalosti studentů z odborné angličtiny. Teoretická část diplomové práce Angličtina pro učitele fyziky mapuje znalosti fyzikální angličtiny studentů Pedagogického asistentství fyziky pro ZŠ a snaží se najít odpověď na otázku, zdali je taková znalost pro budoucí učitele fyziky užitečná. Hlavní část práce přináší učební text, jehož cílem je seznámit budoucí učitele s hlavními fyzikálními termíny v anglickém jazyce. Učební text obsahuje všechna témata, která se probírají v rámci předmětu Fyzika na základních školách, a je rozdělen na soubor anglických textů a cvičení, klíč k těmto cvičením a českoanglický slovník základních fyzikálních termínů.
Abstract Although English is the most widely used language for communication, the level of English of the students of teacher training in science subjects at the Faculty of Education, Masaryk University in Brno is on average very low. The situation gets worse if we consider the knowledge of the subject-specific English. The theoretical part of the diploma thesis English for the Physics Teachers surveys the level of physics-specific English of the students of the Lower Secondary School Teacher Training in Physics and seeks the answer to the question if such knowledge is even useful for the prospective physics teachers. The main part of the thesis comprises of a textbook that focuses on the presentation and practising the basic physics-specific terms in English. The textbook contains all the topics that are dealt with in the lessons of physics at the lower secondary schools in the Czech Republic. It is divided into three parts – English texts and tasks, a key to the tasks and a Czech-English dictionary of the basic physics-related terms.
Klíčová slova anglický jazyk, fyzika, fyzikální angličtina, odborná angličtina, učební text, angličtina pro učitele fyziky
Keywords English language, physics, physics-specific English, subject-specific English, study material, English for physics teachers
Prohlášení Prohlašuji, že jsem závěrečnou diplomovou práci vypracoval samostatně, s využitím pouze citovaných literárních pramenů, dalších informací a zdrojů v souladu s Disciplinárním řádem pro studenty Pedagogické fakulty Masarykovy univerzity a se zákonem č. 121/2000 Sb., o právu autorském, o právech souvisejících s právem autorským a o změně některých zákonů (autorský zákon), ve znění pozdějších předpisů.
V Brně dne 30. 3. 2016
……………………………………
Poděkování Na tomto místě bych rád poděkoval Mgr. Lukáši Pawerovi za ochotu, podnětné rady a vedení této diplomové práce. Dále bych rád poděkoval svým blízkým za podporu při studiu.
Obsah 1.
Úvod ...................................................................................................................................... 7
2.
Anglický jazyk ve fyzice ......................................................................................................... 9
3.
Úroveň fyzikální angličtiny studentů PdF MU ..................................................................... 11
4.
Struktura učebního textu a typy použitých cvičení ............................................................. 14
5.
Metodika práce s učebním textem ..................................................................................... 17 Učební text Angličtina pro učitele fyziky ................................................................................. 19 1.
Measurement.............................................................................................................. 20
2.
Kinematics ................................................................................................................... 25
3.
Dynamics ..................................................................................................................... 31
4.
Rigid Bodies ................................................................................................................. 36
5.
Liquids and Gases ........................................................................................................ 45
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Thermodynamics......................................................................................................... 54
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Electricity..................................................................................................................... 62
8.
Magnetism .................................................................................................................. 70
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Waves and Sound........................................................................................................ 78
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Optics and Light .......................................................................................................... 83
11.
Atomic Physics ............................................................................................................ 90
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Astrophysics ................................................................................................................ 98
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Key............................................................................................................................. 103
14.
Dictionary .................................................................................................................. 128
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Závěr.................................................................................................................................. 158
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Citovaná literatura ............................................................................................................ 159
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Online zdroje ..................................................................................................................... 160
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1. Úvod Angličtina se v dnešní době uplatňuje jako univerzální prostředek komunikace mezi vědci z různých oblastí. Nejinak je tomu i ve fyzice, kde angličtina slouží jako lingua franca, tedy jako univerzální jazyk. Angličtina však není univerzálním komunikačním prostředkem pouze v akademických kruzích, ale i v ostatních oblastech lidského konání. Znalosti absolventů pedagogických oborů zaměřených na výuku přírodovědných předmětů z oblasti odborné angličtiny jsou často velmi nízké. Budoucí učitelé fyziky na základních školách v ČR nejspíše nebudou potřebovat vysokou znalost anglického jazyka k vykonávání svého povolání. Ze zkušenosti, kterou jsem nabyl na praxi na gymnáziu Open Gate a při mých cestách do zahraničí vím, že dobrá znalost předmětu, který chce žák či student rozvíjet, a motivace jsou velmi důležité pro další vzdělání, případně jeho uplatnění na trhu práce. Pokud se však ke znalosti předmětu a motivaci přidá ještě kvalitní znalost cizího jazyka, otevírá se takovému jedinci podstatně více možností. Kvalitní znalost vyučovaného předmětu je pro učitele jedním z nejdůležitějších faktorů úspěšnosti jeho pedagogického působení. Pokud má však učitel alespoň základní znalost cizího jazyka, může pro své studenty čerpat informace z cizojazyčných zdrojů, kontaktovat zahraniční kolegy či integrovat cizí jazyk do výuky přírodovědného předmětu, což v důsledku znamená budování mezipředmětových vztahů a podporu žáků či studentů ve studiu tohoto jazyka. Základem je však učitelova znalost. Pokud učitel sám nebude cizí jazyk umět a nebude znát terminologii z předmětu či předmětů, které jsou primárně objektem jeho zájmu, bude asi těžké žáky či studenty správně motivovat. V rámci terciárního vzdělávání je trendem zavádět výuku některých předmětů v cizím jazyce. Podobně tomu je i na Katedře chemie a fyziky a odborného vzdělávání Pedagogické fakulty Masarykovy univerzity v Brně, kde jsou do budoucna připravovány kurzy pro studenty Učitelství a Pedagogického asistentství fyziky a chemie, které budou vyučovány v anglickém jazyce. I to je jeden z důvodů, proč bude do budoucna znalost odborné angličtiny pro studenty nutností. S ohledem na výše zmíněné vyvstává u studentů Pedagogického asistentství a Učitelství fyziky pro ZŠ potřeba znalosti fyzikální terminologie v anglickém jazyce. Cílem naší práce je tedy vytvořit učební text, který by studentům výše zmíněných oborů pomohl osvojit si právě takovou znalost.
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Práce je rozdělena na teoretický úvod, ve kterém zamýšlíme nad nutností znalosti odborné angličtiny a dále také mapujeme úroveň znalostí z této oblasti u studentů Pedagogického asistentství fyziky pro ZŠ. V Praktické části práce přinášíme učební text, který si klade za cíl seznámit studenty se základní fyzikální terminologií v anglickém jazyce.
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2. Anglický jazyk ve fyzice Pro odborné fyziky, kteří publikují výsledky své práce, využívají cizojazyčných zdrojů a spolupracují se zahraničními kolegy, je znalost jak obecné, tak odborné angličtiny nutností. U učitelů fyziky, kteří působí na základních a středních školách v České Republice, je však situace poněkud jiná. Tito učitelé si většinou vystačí s informacemi, které jsou běžně dostupné v českém jazyce, a na běžných školách se ještě donedávna angličtina ve výuce přírodních věd nijak významněji neuplatňovala. Učitelé fyziky tedy často nemají dostatečnou motivaci ke studiu odborné angličtiny. V současné době je však možno pozorovat trend směřující k výuce některých nejazykových předmětů nebo jejich částí v cizím jazyce. Důraz na zařazování cizího jazyka do výuky i jiných než jazykových předmětu položila i Evropská komise ve svém akčním plánu z let 2005-2006. Jednou z metod zapojení cizího jazyka do hodin ostatních předmětů je metoda CLIL (Content and Language Integrated Learning). Metoda CLIL je založená na výuce předmětu či jeho části v cizím jazyce, při které si žák či student osvojuje znalosti z obou předmětů zároveň. Tato metoda je vhodná pro pedagogy, kteří mají aprobaci k výuce daného jazyka a předmětu, ve kterém chtějí metodu CLIL uplatnit. Ke správné implementaci této metody je nutná učitelova vysoká úroveň cizího jazyka, ale i dobrá znalost druhého předmětu. V projektu Národního institutu pro vzdělávání mělo být do roku 2011 vyškoleno 300 učitelů základních škol a nižších gymnázií v práci metodou CLIL. V současné době se však téměř na žádných běžných základních školách nevyučují nejazykové předměty v cizím jazyce. Mnoho škol na svých webových stránkách uvádí, že se specializují na metodu CLIL. Často jsou však v cizím jazyce (téměř vždy v anglickém jazyce) vyučovány pouze části předmětů jako například tělocvik, pracovní činnosti a informační výchova tedy předmětů, jejichž obsah není tak náročný ve srovnání například s fyzikou či přírodopisem. Na běžných základních školách a nižších stupních víceletých gymnázií se tedy výuka fyziky v anglickém jazyce či alespoň prvky metody CLIL ve větší míře neuplatňuje. Jednou z možných příčin může být nedostatečná znalost anglického (či jiného cizího) jazyka absolventů učitelství přírodovědných předmětů. Jen málo studentů studuje kombinace oborů učitelství cizího jazyka a učitelství některého z přírodovědných předmětů. Pravdou je, že jen málo pedagogických fakult takovou možnost nabízí. V ČR však také existují soukromé základní školy, které většinu předmětů vyučují v anglickém jazyce. Takových škol je jen malé množství a často se jejich vzdělávací plány prolínají s britskými osnovami pro ekvivalentní stupeň vzdělání. Na těchto školách jsou přírodní vědy často realizovány jako jeden vyučovací předmět – Science. 9
Na středních školách je však již situace jiná. V ČR je několik soukromých škol, na kterých je výuka realizována téměř výhradně v cizím jazyce. Příkladem takových škol mohou být gymnázia Open Gate v Babicích u Prahy nebo Porg v Praze a Ostravě - Vítkovicích. Na těchto školách jsou studenti téměř vždy připravováni na složení jak české maturitní zkoušky, tak zkoušky IB (International Baccalaureate, mezinárodní ekvivalent maturitní zkoušky) a následně pak na studium v zahraničí. Zástupcem státem financovaných škol, které se snaží o výuku předmětů v cizím jazyce, je například Gymnázium Slovanské náměstí v Brně. Fyzika se zde však vyučuje kompletně v angličtině pouze v prvním ročníku.
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3. Úroveň fyzikální angličtiny studentů PdF MU Z předchozí kapitoly vyplývá, že výuka fyziky na běžných základních školách není nijak výrazně podmíněna úrovní učitelových jazykových schopností v anglickém nebo jiném cizím jazyce. Nicméně projekty, jako zmiňovaný CLIL, jsou stále častější a angličtina bude pravděpodobně pronikat i do hodin biologie, chemie a fyziky. V současné době se anglický jazyk na některých základních školách vyučuje již od první třídy, což znamená, že studenti přicházející do prvních ročníků na PdF MU mají za sebou často i třináct let studia cizího jazyka. Většina nově příchozích studentů také složila maturitní zkoušku z anglického jazyka a dalo by se tedy očekávat, že úroveň jazykových schopností těchto studentů bude poměrně vysoká. Opak je často pravdou. Studenti bakalářského studijního oboru Pedagogické asistentství fyziky pro ZŠ a navazujícího magisterského oboru Učitelství fyziky pro ZŠ musí projít několika všeobecně zaměřenými kurzy anglického jazyka, nicméně v rámci jejich oboru není zařazen žádný předmět, který by byl zaměřen na oborovou, tedy fyzikální, angličtinu. Jestliže je úroveň angličtiny u nově příchozích studentů nízká, dá se předpokládat, že znalosti z oblasti fyzikální angličtiny budou spíše tristní. Abychom zjistili úroveň fyzikální angličtiny u začínajících studentů fyziky na PdF MU, vytvořili jsme test, který se skládá z pěti cvičení a jedné početní úlohy. Cvičení byla řazena podle složitosti od jednodušších ke složitějším. Účelem sestaveného testu není testovat fyzikální znalosti, ale zjistit úroveň odborné angličtiny, převážně tedy znalosti fyzikálních pojmů v angličtině. V testu jsme použili témata a pojmy, které se běžně probírají již na základní škole, čímž se snažíme eliminovat problémy, které by mohly vzniknout neznalostí dané problematiky. Test samotný je přílohou této diplomové práce. Otestováni byli studenti prvních a druhých ročníků Pedagogického asistentství fyziky pro ZŠ. Maximální počet bodů, kterého bylo možné v testu dosáhnout, byl 50. Průměrný výsledek studentů prvního ročníku byl 14,8 bodu (30 %). Navzdory očekáváním, u studentů druhého ročníku byla situace ještě horší. Studenti druhého ročníku průměrně získali 8,9 bodu (18 %).
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maximální možná úspěšnost
studenti prvního ročníku
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studenti druhého ročníku
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studenti s předpokládanou vyšší znalostí angličtiny
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1. cvičení
2. cv.
3. cv.
4. cv.
5. cv.
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Graf 1: Výsledky testu úrovně fyzikální angličtiny studentů PdF MU
První a třetí cvičení byla zaměřena pouze na znalost slovní zásoby. V prvním z nich bylo úkolem správně vybrat z nabídky jména dvou jednoduchých strojů (pulley a lever) na obrázcích a zaznačit, kde se nachází load a effort. I přesto, že šlo pouze o výběr z možností, jen velmi malé procento studentů dokázalo stroje správně pojmenovat. Nejjednodušší bylo pro studenty označit v obrázku zátěž (load) nejspíš proto, že je to slovo všeobecně známé. Ve třetím cvičení bylo za úkol doplnit chybějící údaje v tabulce (aniž by zde bylo na výběr možností), která se skládala z veličin, jednotek a měřicích zařízení.
Nikdo ze studentů nedoplnil pojmy jako
measuring instrument a quantity i přesto, že slovo quantity bylo použito v zadání. Pojem voltage doplnil pouze jeden student. Zajímavý byl pojem ammeter, který v tomto tvaru nedoplnil nikdo, ale téměř každý napsal nesprávný tvar ampermeter. V druhém cvičení bylo za úkol doplnit slova z nabídky do souvislého textu. Z 8 slov, která bylo potřeba doplnit, většina studentů doplnila 3 až 6 slov správně. K doplnění zde byla například slova jako charge, attract nebo repel, která většina studentů doplnila správně. Nejvíce se zde chybovalo ve správném dosazení pojmů weight a mass. Téměř všichni tyto pojmy zaměnili. Důvody mohou být dva – neporozumění těmto pojmům po fyzikální stránce nebo nesprávné porozumění větám, do kterých se tyto pojmy měly dosazovat Čtvrté a páté cvičení byly, s ohledem na výsledky, nejtěžší. Ve čtvrtém cvičení bylo úkolem formulovat Archimedův zákon. Nápovědou byla studentům tabulka, ve které bylo možné najít všechny termíny potřebné k formulaci daného zákona. Nikdo ze studentů nebyl 12
schopen napsat srozumitelnou a dostatečně přesnou formulaci Archimedova zákona. Několik studentů se o tuto formulaci pokusilo, nicméně tyto pokusy byly natolik fyzikálně nepřesné či gramaticky a jazykově nesrozumitelné, že je bylo možné akceptovat. V pátém cvičení bylo za úkol popsat obraz vytvořený rovinným zrcadlem. Nápovědou byl v tomto případě pouze obrázek, ze kterého bylo možné odvodit fyzikální vlastnosti daného obrazu. Přesto že ke splnění úkolu stačilo napsat tři vlastnosti - the same size as the object, laterally inverted, virtual – nikdo tyto vlastnosti (ani v jiné formulaci) neuvedl. Posledním, šestým, úkolem byla početní úloha. Studenti si mohli vybrat ze dvou úloh. První byla z oblasti hydrostatiky a druhá z kinematiky. U těchto cvičení nešlo o produkci jazyka, ale o správné pochopení textu, které je základem ke správnému výpočtu úlohy. Správně vypočítal úlohu pouze jeden student. Několik dalších studentů uvedlo výpočty, ze kterých bylo vidět porozumění textu, ale nedospěli ke správným výsledkům. Přestože se tyto úlohy počítají s žáky na základních školách, lze předpokládat, že hlavním zdrojem neúspěchu nebylo neporozumění textu, ale neschopnost najít správné řešení. V rámci mapování situace jsme otestovali i několik studentů vyšších ročníků, kteří byli na studijním pobytu v zahraničí nebo studují anglický jazyk, jako svůj druhý obor na PdF MU. Výsledky těchto studentů byli podstatně lepší a pohybovaly se v rozmezí 31 až 44 bodů (63 až 89 %). Tyto výsledky jsou pouze orientační, protože nelze posoudit vliv vyšší znalosti fyziky, nicméně je pravděpodobné, že vyšší znalost anglického jazyka sehrála svou roli v úspěšnosti těchto studentů. Při šetření, které jsme provedli na studentech prvních a druhých ročníků Pedagogického asistentství fyziky pro ZŠ, nemůžeme vyloučit vliv nedostatečné znalosti fyziky. Nicméně i přes tento fakt, lze na základě výsledků konstatovat, že znalost anglických ekvivalentů fyzikálních pojmů a schopnost vytvořit fyzikálně zaměřený text v anglickém jazyce jsou mizivé.
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4. Struktura učebního textu a typy použitých cvičení Z předchozích kapitol vyplývá, že znalosti budoucích učitelů fyziky z oblasti fyzikální angličtiny jsou velmi nízké, ale je nepochybné, že alespoň základní znalost fyzikálních termínů v angličtině by byla užitečná a využitelná například při práci metodou CLIL nebo při vyhledávání informací v cizojazyčných zdrojích. S ohledem na výše zmíněné jsme vytvořili učební text nazvaný Angličtina pro učitele fyziky (English for Physics Teachers), jehož cílem je studentům v anglickém jazyce přiblížit terminologii z různých oblastí fyziky. Pomocí různých typů cvičení jsou studenti vedeni k osvojení těchto termínů a následně je rozvíjena schopnost tyto pojmy aktivně používat. Angličtina pro učitele fyziky není učebnicí fyziky ani učebnicí anglického jazyka, je to učební text prezentující a procvičující fyzikální pojmy a anglickém jazyce. Učební text je rozdělen na tři na sebe navazující části. Hlavní a první částí je soubor textů a cvičení, který je dále rozdělen na dvanáct podkapitol. Témata těchto podkapitol jsou následující: Measurement, Kinematics, Dynamics, Rigid Bodies, Liquids and Gases, Thermodynamics, Electricity, Magnetism, Waves and Sound, Optics and Light, Atomic Physics a Astrophysics. Tato témata byla vybrána tak, aby jednak korespondovala se strukturou kurzů odborné fyziky v rámci bakalářského studia Pedagogického asistentství fyziky pro ZŠ, ale také aby korespondovala s obsahem předmětu Fyzika, který je vyučován na běžných základních školách v ČR. Druhou částí je klíč ke cvičením z první části a tento je následován slovníkem, tedy seznamem hlavních termínů z daných oblastí fyziky a jejich anglických ekvivalentů. Klíč i slovník jsou rozděleny, stejně jako první část, na dvanáct podkapitol tak, aby s první částí korespondovaly. V každé z dvanácti kapitol hlavní části najdeme jeden až dva texty, které jsou vždy následovány otázkami. Tyto otázky zjišťují porozumění danému textu nebo úzce souvisí s tématem, které je rozebíráno v textu. Texty jsou převzaty ze zahraničních učebnic fyziky různých úrovní, většinou vydaných v nakladatelství Oxford University Press, což zaručuje jejich autenticitu. Některé z textů jsou převzaty z českých publikací typu reader. Tyto readery jsou v podstatě sborníky odborných textů určité obtížnosti doplněné o cvičení vztahující se k daným textům. Studenti se zde angličtinu učí pouze prostřednictvím čtení s porozuměním. Náš učební text využívá jednak čtení s porozuměním, ale i cvičení, kde musí student aktivně jazyk produkovat. Čtení s porozuměním je nicméně velmi přínosné, protože student jednak vnímá fyzikální termíny v kontextu dané situace a na druhou stranu jasně vidí i jazykové aspekty 14
použití těchto termínů. Tento typ cvičení také napomáhá rozvoji schopnosti se orientovat v textu, což koresponduje s cílem zlepšit schopnost studentů vyhledávat informace v cizojazyčných textech. Se čtením s porozumění úzce souvisí i následující typy cvičení. První z nich je seřazování instrukcí podle jejich logického sledu a přiřazování pojmů k jejich popisu či definici. Tato cvičení seznamují studenty s fyzikálními termíny v širším kontextu, ale rozsahy textů jsou podstatně menší. Student sám nemusí produkovat žádné jazykové struktury, ale ke správnému vyřešení musí velmi dobře rozumět kratším textům, se kterými pracuje. S porozuměním textu pracují také cvičení, která jsou postavena na doplňování slov z nabídky do delšího souvislého textu. Student zde nemůže slova pouze slepě doplnit, ale musí případně slovo upravit tak, aby do věty sedělo jak po jazykové, tak po významové stránce. Posledním typem cvičení, které souvisí se čtením s porozuměním, jsou početní úlohy. Přestože při řešení početních úloh neprodukuje student žádný jazyk (mimo slovní odpovědi), zařadili jsme úlohy do našeho učebního textu právě proto, že u početních úloh je správné porozumění zadání nutným předpokladem k úspěšnému řešení. Další cvičení, která v učebním textu používáme, můžeme rozdělit na dvě skupiny. První skupina se vyznačuje tím, že student nemusí sám produkovat složitější jazykové struktury, ale pracuje s jednotlivými fyzikálními termíny. Zde můžeme zařadit popis obrázků – student musí z nabídky vybrat a přiřadit správný fyzikální termín k dané části obrázku, doplnění chybějících pojmů do tabulky – student musí z fyzikálního hlediska tabulce rozumět a vyhledat anglické ekvivalenty chybějících pojmů nebo rozdělování předložených pojmů do skupin podle určitého kritéria. Tyto typy cvičení mají jednu společnou výhodu a tou je, že se jejich prostřednictvím student rychle seznámí s velkým množstvím termínů. Další z předností je, že je lze považovat z jazykového hlediska za jednodušší a tedy vhodné i pro studenty s celkovou nižší úrovní angličtiny. Pokud student pochopí zadání a fyzikální podstatu, není většinou problém správné pojmy dohledat. Nespornou nevýhodou je, že fyzikální termíny jsou zde izolované a student s nimi nemusí nijak pracovat (upravovat nebo je spojovat do větších celků). Z toho vyplývá, že tato cvičení nijak nerozvíjí produkci jazyka, ale jsou zaměřena pouze na osvojení si daného slova nebo slovního spojení. Ve cvičeních, která bychom zařadili do druhé skupiny, musí student aktivně produkovat větší jazykové celky a to s pomocí předložených termínů či obrázků, které objasňují danou fyzikální problematiku. Takovým typem je například popis fyzikálního jevu, který je zobrazen na obrázku (u složitějších popisů jsou přiloženy seznamy termínů, které je v popisu možno využít), 15
vytváření testových otázek nebo formulace fyzikálních zákonů. Taková cvičení jsou mnoha studenty považována za složitá, protože nejenom, že student musí znát dané fyzikální termíny v cizím jazyce, ale musí být schopen tyto termíny upravit a správně použít ve větě tak, aby výsledný celek byl jak z fyzikálního, tak z jazykového korektní. Tato cvičení jsou velmi komplexní a právě tato komplexnost může být pro mnoho studentů odrazující. Nespornou výhodou je však to, že trénují schopnost aktivně jazyk tvořit. Při sestavování učebního textu jsme se řídili dvěma předpoklady. Většina ze studentů přicházejících na PdF MU složila maturitní zkoušku z anglického jazyka, takže za vstupní úroveň jazykových znalostí a schopností považujeme úroveň intermediate (středně pokročilí; B2 podle CEFR). Dalším předpokladem je znalost fyziky alespoň na úrovni základní školy. S ohledem na to, že studenti mohou mít různou úroveň angličtiny, se liší obtížnost cvičení tak, aby se zvětšila cílová skupina našeho učebního textu. Pro lepší orientaci v textu jsou použity piktogramy, které použitým symbolem označují jednotlivé typy cvičení a svou barvou naznačují jejich obtížnost. Pro zpestření učebního textu a zvýšení motivace studentů jsme zavedli samostatné boxy, které poukazují za zajímavé fakty týkající se fyziky z prostředí anglicky mluvících zemí. Učební text je následován klíčem k použitým cvičením a slovníkem fyzikálních termínů. Tento slovník obsahuje přibližně 800 hesel z oblastí fyziky, které korespondují s tématy kapitol v učebním textu. Slovník nemá ambice konkurovat běžně dostupným slovníkům, ale snaží se studentovi dodat většinu odborných termínů, které by mohl využít jak při vypracovávání cvičení, tak při čtení jiných textů týkajících se dané oblasti fyziky.
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5. Metodika práce s učebním textem Koncepce učebního textu je založena na samostatné práci studenta a objem poznatků, které si student osvojí tak do značné míry závisí na jeho osobním přístupu. Při práci s tímto učebním textem doporučujeme dodržovat následující postup: 1. Seznámit se slovní zásobou dané kapitoly. K tomuto účelu je určen slovník fyzikálních pojmů, jehož rozdělení koresponduje s kapitolami samotného učebního textu. 2. Přečíst článek/články v dané kapitole. V každé kapitole doporučujeme začít článkem, tedy čtením s porozuměním. Každý z článků je tvořen přehledem a překladem náročných slov, která se v textu vyskytují, textem samotným a otázkami, které zjišťují porozumění danému textu. 3. Vypracovat cvičení v dané kapitole. Cvičení nejsou řazena od jednodušších k obtížnějším, ale jsou řazena s ohledem na obsah. Pokud chce student postupovat od jednodušších cvičení ke složitějším, lze se orientovat podle piktogramů, jejichž rozdělení a popis je uveden níže. 4. Zkontrolovat odpovědi pomocí klíče. Řazení klíče koresponduje s řazením výše zmiňovaných cvičení. Některá cvičení mají pouze jednu správnou odpověď, která zde uvedena. Odpovědi v ostatních cvičeních, např. popisy fyzikálních jevů, nemají pouze jednu správnou odpověď. Správná řešení takových cvičení, která jsou uvedena v klíči, jsou pouze jednou z možných formulací. Při samostatné práci s učebním textem by měl student najít většinu slov týkajících se fyzikálních pojmů ve zmiňovaném slovníku. Některé výrazy, které považujeme za náročné, jsou přeloženy přímo u jednotlivých cvičení a textů, ve kterých se vykytují. Nelze však postihnout všechna slova, která by studenti nemuseli znát. Doporučujeme tedy spolupracovat s anglickočeským překladovým nebo anglickým výkladovým slovníkem. Není také vyloučeno používat internet jako zdroj informací. Orientaci v učebním textu usnadňují piktogramy. Symbol v piktogramu odkazuje na druh cvičení; jeho barva pak značí náročnost cvičení (modrá – jednoduché, červená – střední, černá – těžké). piktogram název
význam
reading
čtení s porozuměním
questions
otázky k textu
problem solving
početní úloha
easy task
jednoduché cvičení, např. popis obrázku
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medium task
středně těžké cvičení, např. doplnění slov do textu
difficult task
těžké cvičení, např. popis fyzikálního jevu vlastními slovy
Jako poslední část uvádíme přehled frází, které se opakují v instrukcích k jednotlivým cvičením. fráze
český ekvivalent
complete the table
doplň tabulku
cross out
vyškrtni
describe
popiš
divide
rozděl
estimate
odhadni
fill the gaps with the words from the box
doplň do textu slova z rámečku
look at
podívej se na
match the terms with the definitions
přiřaď pojmy k jejich definicím
put instructions in order
seřaď instrukce
read the text and answer the following questions state
přečti text a odpověz na otázky uveď
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Učební text Angličtina pro učitele fyziky
19
1. Measurement 1. Read the text and answer the following questions. abundance accurate bar cross-section dimension employ inconvenient initially
nadbytek, spousta přesný tyč průřez rozměr použít nevhodný původně, nejprve
intend meridian preserve purpose recommend reject sufficient work out
mít v úmyslu, hodlat poledník zachovat účel doporučit odmítnout dostatečný vypracovat
Measurement of Length The basic metric unit of distance, and length in general, is the metre. The standard metre was taken as the distance between two lines on a platinum-iridium bar kept at the International Bureau of Weights and Measures in Paris. The material, cross-section and conditions of storage of this standard metre bar, called the international prototype metre, were so selected as to preserve the dimensions as accurate as possible. For one thing, measures were taken to maintain a constant temperature of the bar. Accurately made copies of prototype metre were supplied to the institutes of weights and measures of various countries for reference purposes. It was initially intended to make the metre equal to one-ten-millionth of Earth’s meridian quadrant at sea level. But it was found that the accuracy of measurements on the Earth’s surface was not sufficient. However, the idea of making a new metre or introducing corrections on the basis of more accurate measurements was rejected and the prototype metre was left as it was. This metre is about 0.2 mm smaller than one ten-millionth of Earth’s meridian quadrant. The so-called British imperial units are widely used in Great Britain, the USA and some other countries. These include the following: inch foot statute mile nautical mile
(1’’ = 25.4 mm) (1’ = 12’’ = 304.8 mm) (1 sta mi = 1.609 m) (1 naut mi = 1.852 m)
In UK and US English, a period (.) is used as a decimal separator: 27.5 A comma (,) is used to separate thousands: 356.851,7
The existence of an abundance of various units of length (or other physical quantities) is very inconvenient in practice. For this reason, international standard definitions of the units of all physical quantities were worked out in recent years. This system of units, known as the SI (Systeme Internationale) system, was recommended for use since 1963. (Herzlík, 1987, p. 1) a. What does the standard metre kept at the International Bureau of Weights and Measures look like? b. What was the first definition of the metre? 20
c. Why was the SI system introduced? d. Is there any basic unit of length apart from the meter in the SI system? What other units do you know? a.
b.
c.
d.
2. There are seven basic units in the SI system. Complete the table. Unit
Unit Symbol
metre
Physical Quantity length
kg second
balance, scales time
A
ammeter thermodynamic temperature
kelvin mol candela
Measuring Instrument
--luminous intensity
---
3. All other units used in physics are either dimensionless or they can be expressed as a product of one or more basic units. These are called derived units. State at least five derived units, their unit symbol and the corresponding physical quantity. a. b. c. d. e. 21
4. The abundance of various units causes problems not only among the scientific community. Match the units with their values. 25.4 mm
304.8 mm
1.852 km/h
0.454 kg
3.785 l
914.4 mm
568.261 ml
1,193.256 km/h
29.573 ml
1,609.3 m
159 l
4.564 l
unit
value
unit UK gallon (gal)
foot (ft)
US gallon (gal)
yard (yd)
US barrel (barrel)
statute mile (mi) US fluid ounce (fl oz)
When you stop at the gas station anywhere in the US, you will buy gas or diesel in gallons. That is not true in the UK. There you will buy petrol or diesel in litres.
value
inch (in)
The unit of gallon has its origin in England where it served as the base of systems for measuring wine and beer. The wine gallon was smaller and the size is equal to the today’s US gallon. The imperial (UK) gallon is bigger and its size is equal to the former beer gallon.
knot (kn/kt) mach (Ma/M)
UK pint (pt)
Picture 1: A Gas can (MJCdetroit, 2008)
pound (lb)
5. For measurements on very large or very small scales the SI system introduces the prefixes such as milli, centi and kilo. The table below shows the most frequently used ones. factor 10
9
10
6
10
3
102 10
a. b. c. d. e. f.
1
prefix giga mega
symbol G M
factor
prefix
symbol
10
-1
deci
d
10
-2
centi
c
-3
milli
m
micro
µ
nano
n
kilo
k
10
hekto
h
10-6
deka
da
10
-9
Answer the following questions using the approximate values and the correct prefixes. What is the value of the atmospheric pressure at the sea level? What is the amount of liquid in a regular glass of wine? What is the value of Earth radius? What is the range of wavelengths of the visible spectrum of light? What is the highest frequency a man can hear? What is the clock rate of the up-to-date CPUs?
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a.
b.
c.
d.
e.
f.
6. Read the article. Based on the text, create 2 two questions that can be used in as test questions for your students. State also the answers that you would require. See the example. Example: What is a pendulum? Pendulum is an instrument which can be used to investigate time. It consists of a string and a small mass attached to it. button divide investigate overcome pendulum
tlačítko dělit zkoumat, vyšetřit překonat kyvadlo
result rigid string swing
výsledek tuhý provázek, vlákno kyv
Measuring Time Time intervals of many seconds or minutes can be measured using a stopclock or stopwatch. Some instruments have an analogue display, with a needle (‘hand’) moving round a circular scale. Others have digital display, which shows a number. There are buttons for starting the timing, stopping it and resetting the instrument to zero. With a hand-operated stopclock or stopwatch, making accurate measurements of short time intervals (a few second or less) can be difficult. This is because of time it takes you to react when you have to press the button. Fortunately, in some experiments, there is a simple way of overcoming the problem. Here is an example:
Picture 2: Pendulum
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The pendulum above takes about two seconds to make one complete swing. Provided the swings are small, every swing takes the same time. This time is called period. You can find it accurately by measuring the time for 25 swings, and then dividing the result by 25. For example: Time for 25 swings = 55 seconds So: time for 1 swing = 55/25 seconds = 2.2 seconds (Pople, 2010, p. 14)
question:
answer:
7. After reading the article Measuring Time design a procedure that would allow you to measure most precisely thickness of a sheet of paper using only a ruler.
8. Vernier calliper is another instrument used to measure length. To achieve more precise measurement there are two scales. Put the instructions in the right order. State also what the result of this measurement is.
Picture 3: Vernier calliper (Advanced Instructional Systems and North Carolina State University, 2010)
a. Read this division on the vernier scale. b. Put the values together using a decimal point. c. Read the highest division on the main scale. d. See where divisions of the both scales coincide. 24
2. Kinematics 1. Read the article and answer the following questions. arrow direction indicate
šipka směr naznačovat, ukazovat
initial journey magnitude
počáteční cesta, vzdálenost velikost
Speed If a car travels between two points on a road, its average speed can be calculated like this: average speed =
distance moved time taken
If distance is measured in metres (m) and time in seconds (s), speed is measured in metres per second (m/s). For example: if a car moves 90 m in 3 s, its average speed is 30 m/s. On most journeys, the speed of car varies, so the actual speed at any moment is usually different from the average speed. To find an actual speed, you need to discover how far the car moves in the shortest time you can measure. For example, if a car moves 0.20 metres in 0.10 s: speed =
0.20 m = 20 m/s 0.10 s
Velocity Velocity means the speed of something and its direction of travel. For example, a cyclist might have a velocity of 10 m/s due east. On paper, this velocity can be shown using an arrow. For motion in a straight line you can use + or – to indicate direction. For example: + 10 m/s (velocity of 10 m/s to the right) - 10 m/s (velocity of 10 m/s to the left) Note: + 10 m/s may be written without the +, just as 10 m/s. Quantities such as velocity, which have a direction as well as a magnitude (size) are called vector. Acceleration Something is accelerating if its velocity is changing. Acceleration is calculated like this: average acceleration =
change in velocity 𝑣−𝑢 ,𝑎 = time taken 𝑡
where u is the initial velocity and v is the final velocity. For example, if a car increases its velocity from zero to 12 m/s in 4 s: average acceleration = 12/4 = 3 m/s2 Note that acceleration is measured in metres per second2 (m/s2).
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Acceleration is a vector. It can be shown using an arrow (usually double-headed). Alternatively, a + or – sign can be used to indicate whether the velocity is increasing or decreasing. For example: + 3 m/s2 (velocity increasing by 3 m/s every second) (Pople, 2010, p. 26) a. What is the difference between speed and velocity? b. Why is the actual (instantaneous) speed of a moving car usually different from its average speed? c. What are the two components of every vector? d. How do we call the motion which is steady (involves no acceleration) and the one which is accelerated or decelerated? e. Create a test question for your students. You want to test their ability to calculate average speed if given time and distance. a.
b.
c.
d.
e.
2. Estimate the speeds and complete the table. m/s human walk motorway speed limit in the Czech Republic the speed of sound in dry air at sea-level pressure and 20 °C the speed of light in vacuum
km/h
Speed is usually measured in m/s or in km/h. In some parts of the world mph (miles per hour) is used more frequently; especially in the UK and in the US. Other units of speed are knots (nautical mile per hour, kn/kt), feet per second (ft/s) or Mach number (speed divided by the speed of sound). 1 mph=1.609 km/h 1 kn=1.852 km/h 1 ft/s=1.097 km/h 1 Mach=1225.044 km/h
26
3. Match the terms with their definitions. speed
velocity
acceleration
The speed and direction of an object. The velocity of a moving object changes if either its speed or its direction changes. For example, if a car travels around a corner at a constant speed, its velocity changes because the car is changing direction. (Tulajová, 2000, p. 63) The rate of change of velocity. When the velocity of an object increases, it is accelerating. Acceleration is a change in velocity over a certain amount of time. When velocity decreases, the rate of change is called deceleration. (Tulajová, 2000, p. 63)
The rate at which an object moves. It is the measurement of the distance travelled by an object in a certain unit of time. (Tulajová, 2000, p. 63)
4. There are various types of motion. Match them with their descriptions and add real-life examples. non-uniform translational
oscillatory uniform
rotational
motion
description
example
covers equal distance in equal interval of time covers unequal distances in equal interval of time is repetitive and fluctuates between two locations
occurs when an object spins
results in a change of location
27
5. There are four graphs illustrating the motion of a car. The car moves along a straight line and the values of distance and time are recorded. Two of the graphs are already described for you. Describe the other two graphs. Write as much as you can read from the graphs. B 100 80 60 40 20 0
distance/m
distance/m
A
0
1
2
3
4
100 80 60 40 20 0
5
0
1
2
time/s
time/s distance/m
0 0
1 20
2 40
3
4
5
4 70
5 100
time/s
3 60
4 80
5 100
The car is travelling at steady speed. The line rises by 20 m for every 1 s so the motion is uniform.
0 0
1 10
2 25
3 45
The car is accelerating. It travels further every second. The motion is accelerated thus non-uniform.
D 100 80 60 40 20 0
distance/m
distance/m
C
time/s distance/m
0
1
2
3
4
5
100 80 60 40 20 0 0
1
2
time/s
time/s distance/m
0 100
1 70
2 45
3
4
5
time/s
3 25
4 10
5 0
time/s distance/m
0 0
1 20
2 40
3 40
4 40
5 40
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6. Fill the gaps in the description of free fall with the terms in the box. acceleration
air resistance
mass
vertical
Falling Objects A very important example of uniformly accelerated motion is the ________ motion of an object in a uniform gravitational field. If we ignore the effects of ___ __________, this is known as being in free-fall. In the absence of air resistance, all falling objects have the same ____________ of free-fall, independent of their ____. (Kirk, 2014, p. 11) 7. Read the article about Brownian motion and answer the following questions. adjacent behaviour contain countless evenly instant
sousední, přilehlý chování obsahovat nespočet rovnoměrně okamžik
pollutant spread subject to tend to tissue undergo
škodlivina šířit se podléhat tíhnout, mít sklon k tkáň podstoupit, procházet
Brownian motion Brownian motion, also called Brownian movement, any of various physical phenomena in which some quantity is constantly undergoing small, random fluctuations. It was named after the Scottish botanist Robert Brown, the first to study such fluctuations (1827). If a number of particles subject to Brownian motion are present in a given medium and there is no preferred direction for the random oscillations, then over a period of time the particles will tend to be spread evenly throughout the medium. Thus, if A and B are two adjacent regions and, at time t, A contains twice as many particles as B, at that instant the probability of a particle’s leaving A to enter B is twice as great as the probability that a particle will leave B to enter A. The physical process in which a substance tends to spread steadily from regions of high concentration to regions of lower concentration is called diffusion. Diffusion can therefore be considered a macroscopic manifestation of Brownian motion on the microscopic level. Thus, it is possible to study diffusion by simulating the motion of a Brownian particle and computing its average behaviour. A few examples of the countless diffusion processes that are studied in terms of Brownian motion include the diffusion of pollutants through the atmosphere, the diffusion of “holes” (minute regions in which the electrical charge potential is positive) through a semiconductor, and the diffusion of calcium through bone tissue in living organisms. (Brownian motion, 2016) a. Is the term Brownian motion related only to the movement of particles? b. There are two adjacent regions that are connected. One of the regions contains higher number of certain particles. What happens? c. What is the name of the physical process in which the particles tend to spread steadily from the regions of high concentration to the regions of low concentration? d. What experiments would you use to demonstrate this phenomenon to your students? 29
a.
b.
c.
d.
8. Maglev train can travel at a maximum speed of 505 km/h. What is the distance between Tokyo and Osaka if the journey takes 1 hour and 7 minutes?
30
3. Dynamics 1. Read the text and answer the following questions. arrow direction float charged pull push resistance
šipka směr vznášet se, plovat nabitý táhnout, tah tlačit, tlak odpor
rope shape slide slow down speed up string wire
lano tvar klouzat, posunovat zpomalit zrychlit provázek, vlákno drát
Introduction to Forces What is a force? When a tennis ball hits the ground, a force changes its shape, speed, and direction. A force is a push or pull that can change the shape of an object, or change the way that it moves. You cannot see forces but you can see what they do. If something starts to move, or speeds up, a force is acting on it. Forces can also slow things down or stop them moving. If an object is already moving, a force can change the direction of motion. Force arrows You can show the force acting on an object by drawing an arrow. The length of the arrow shows the size of the force. The direction of the arrow shows the direction of the force. The arrow is in contact with the object. Different types of force Attracting and repelling The gravitational force, or force of gravity, is the force that attracts you to the Earth. It is also the force that attracts the Earth to you! The force of gravity acts between any objects that have mass. On Earth, the force of gravity on an object is called the object’s weight. This force acts towards the centre of the Earth. It always pulls you down, whenever you are on the Earth. A different kind of force is an electrostatic force, which acts between objects that are charged. Rubbing plastic objects can charge them up with static electricity. Once charged they can attract or repel other charged objects. Magnets attract magnetic materials such as iron, steel, or nickel. There is a magnetic force between the magnet and the magnetic material. The objects do not need to be touching to experience the force. It’s the same with gravitational and electrostatic forces. Forces on moving objects Friction is another type of force. When any object slides across a surface, the force of friction tries to stop it moving. Air resistance is a force that acts on any object moving through the air. Water resistance acts on any object moving through water. Both air resistance and water resistance are types of drag. The moving object collides with the particles in the air or the water, and this slows it down. In a car or plane, a force called thrust pushes the vehicle forwards. 31
Upthrust and tension If an object is floating, the water is pushing it up. This push is a force called upthrust. Balloons also experience upthrust because the air below the balloon pushes up. If you pull something with a rope, there is tension in any rope, wire cable, or piece of string that has a weight on it. (Reynolds, 2013, p. 8) a. b. c. d.
What can happen if a force acts on an object? Is a force vector or scalar? Why? What symbol do we use if we want to draw a force? What types of forces does the article mention? What other forces do you know? What objects exert an electrostatic force? If there are two such objects close to each other, when do they attract/repel each other? e. If you throw a plastic bottle into the water it floats. Why is it so? a.
b.
c.
d.
e.
2. Force is measured by a device called force meter. The force meter in the pictures is usually used in physics lessons. Describe how it works. You can use the expressions in the box. apply extension force
hook newton pull
push reading return
scale spring stretch
Picture 4: Force meter (Team Strauss)
32
3. Fill the gaps in the definitions of Newton’s laws of motion and answer the following questions. direction
interact
net force
velocity
Newton’s First Law If no force acts on a body, the body’s ________ cannot change; that is, the body cannot accelerate.
Isaac Newton was an English mathematician, astronomer and physicist. He published his theory of gravity and the three laws of motion in 1686 in his Philosophiae Naturalis Principia Mathematica.
Newton’s Second Law The ___ _____ on a body is equal to the product of the body’s mass and it acceleration. Newton’s Third Law When two bodies ________, the forces on the bodies from each other are always equal in magnitude and opposite in _________. (Walker, Halliday, & Resnick, 2014, p. 106)
Picture 5: Isaac Newton (Kneller, 1689)
4. Force is a vector quantity which means that it has both the magnitude and direction. There are various quantities in the box bellow. Divide them between scalars and vectors. acceleration area density
displacement distance energy
scalars
force mass momentum
potential difference speed velocity
vectors
33
5. If there are two forces acting upon a body we can use the parallelogram rule to find the resultant (the net force). Put in order the instructions to this method.
To find the resultant of two vectors: Draw in the diagonal from O and measure its length. The diagonal represents the resultant in both magnitude and direction. (Below, for example, the resultant is a force of 60 N at 26° to the horizontal.) On paper, draw two lines from O to represent the vectors. The directions must be accurate, and the length of each line must be in proportion to the magnitude of each vector. Draw in two more lines to complete a parallelogram.
6. Read the article about rolling friction and answer the following questions. Rolling Friction cylinder require uniformly exert
válec vyžadovat rovnoměrně působit
pressure instead of employ pressure
Let us take a wooden cylinder and place it with its side on a table. Let us now insert the ends of a wire fork into holes in the ends of the cylinder, and attach the fork to a very sensitive dynamometer. If we pull the dynamometer, the cylinder will roll along the table. The dynamometer will show that a very small force is required to start the cylinder and move it uniformly, a force much less than if the cylinder were placed with its end on the table and made to slide. The force exerted by the table on a rolling cylinder is called the force of rolling friction. With the same force of pressure acting on the table, the force of rolling friction is much less than that of sliding friction. For example, when steel wheels run along steel rails, the rolling friction is about one-hundredth of sliding friction. (Herzlík, 1987, p. 59)
tlak místo zaměstnat, využít tlak Bearings are mechanical elements used to reduce fiction. One type is a bearing with a rolling element, for example a ball bearing or roller bearing.
Picture 6: Ball bearing (Mahalaxmi Bearing Co., 2016)
a. This article speaks about rolling friction. Is there any other type friction? Describe it. b. What experiments would you use to demonstrate friction when teaching? Describe them in one or two sentences. c. How can we reduce friction? 34
d. Look at the picture depicting rolling friction. Create a comprehensible explanation of this phenomenon. You can use the information in the box.
Picture 7: Rolling friction (Král, 2008)
forces of adhesion act between the surfaces a rolling body constantly “climbs a hill” a ball or cylinder rolls along the surface of another body the harder the surfaces, the smaller the rolling friction a rolling body slightly presses into the surface
35
4. Rigid Bodies 1. First read the description of a rigid body and then the article about the centre of mass. Answer the following questions. as if definite environment involving simplify
jako by určitý prostředí zahrnující zjednodušit
squeeze stretch twist undergo
zmáčknout natáhnout otočit prodělat, podstoupit
Rigid Body In physics, a rigid body is an idealized model of an object that has a definite and unchanging shape and size. In reality, real-world bodies are constantly interacting with the environment, undergoing forces that can twist, stretch, or squeeze them in ways that would make precise calculations involving them quite impractical. To simplify things, we often (when possible) try to treat the object as if it is not undergoing these types of deformations. (Jones, 2008)
apply broom carry clockwise
uplatnit, použít koště nést ve směru hodinových ručiček
evenly plank shape shoulder
rovnoměrně deska tvar rameno
Centre of Mass If you want to carry a plank of wood on your shoulder, you need to place it underneath the middle of the plank. There is a point in an object through which all of the weight of an object seems to act, called the centre of mass (or centre of gravity). The centre of mass is in the centre of the plank of wood. If this point is above your shoulder, which is the pivot, there is no turning force acting on the plank of wood. If you move the pivot closer to one end of the plank, there will be a turning force on the plank. The plank’s weight acts through its centre of mass to produce a turning force that turns the plank clockwise. To balance it you will need to apply another force. This force will turn the plank anticlockwise and balance its weight. The centre of mass of a regular shape, such as a cube or a ball, is in the centre of the shape because the mass is evenly distributed throughout the object. For an irregular shape such as a broom, the entre of mass will not be in the centre. (Reynolds, 2013, p. 176) a. What is a rigid body and why do we use it? b. What is a centre of mass? c. Is really the wooden plank a rigid body?
36
a.
b.
c.
2. One method how to determine the centre of mass of an irregularly shaped object is to use a plumb as it is shown in the picture below. Write down a set of instructions for your students how to carry out this method. You can use the words in the box. cross different point hang
intersect plumb plumb line
suspend from/at upward force from the pin weight
Picture 8: How to find the centre of gravity (BBC, 2014)
1.
2.
3.
4.
5.
37
3. The stability of an object depends on the position of its centre of mass. There are three pictures of a stool in different positions with a few words below each of them. Look at the pictures and describe in full sentences what is happening with the stool. stool tip over
židle překlopit, převrátit se
tilt
nahnout, naklonit
Picture 9: A stool at three stages of toppling (BBC, 2014)
equilibrium, balanced, no turning effects
small tilt, turn back, original position
large tilt, tip over
a.
b.
c.
4. There are three types of equilibrium – stable, unstable and neutral. We call them equilibrium positions. Draw the pictures representing these three positions.
38
5. Turning effects of forces are described with the quantity called moment of force. Read the paragraph about this quantity and fill the gaps in the formula for its calculation. It is difficult to tighten a nut with your fingers. But with a spanner, you can produce a larger turning effect. The turning effect of a force is called a moment. It is calculated like this: moment of a force about a point = _____ × perpendicular ________ from the point Moments are described as clockwise or anticlockwise, depending on their direction. The moment of a force is also called a torque. a. Look at the picture bellow. There are two people on a seesaw. Decide whether the seesaw is in equilibrium and explain why it is so.
Picture 10: Seesaw (Pass My Exams, 2016)
b. Look at the second picture and decide in which case the person closing the doors has to act with bigger force. Are the moments of those two forces the same or different?
Picture 11: Doors (TutorVista, 2016)
39
6. Simple machines are devices that change the force applied to it. The force that is applied to one part of the machine is called the effort. The force that the machine produces acts against the load. Match the types of simple machines with their descriptions. inclined plane wheel and axle
lever screw
pulley
a bar that turns on a pivot in order to exert a force a grooved wheel, or set of wheels, around which a rope passes in order to move a load a rotating devices that exerts a force at its centre when the outer part is turned, and vice versa a shaft with a spiral groove a slope that reduces the effort needed to move something
7. We usually divide levers into two types – the first-class and second-class lever. Look at the pictures and decide which of them is the first-class and which of them is second-class. There is one more type: third-class lever. The load is located at one side of the effort and the fulcrum is located on the other. Real-life example is a hammer or a pair of tweezers.
Picture 13: Levers
a. Explain the difference between the first-class and the second-class levers. b. State at least two examples of each class that you use in real life.
Picture 12: Tird-class lever
40
8. Read the article about work and energy and answer the following questions. although dig knock over meaning petrol
ačkoliv kopat převrhnout smysl benzín
precise spring tank whenever
přesný pružina nádrž kdykoliv
Work In everyday language, work might be writing an essay or digging the garden. But to scientists and engineers, work has a precise meaning: work is done whenever a force makes something move. The greater the force and the greater the distance moved, the more work is done. The SI unit of work is the joule (J): 1 joule of work is done when a force of 1 newton (N) moves an object 1 metre in the direction of the force. Work is calculated using this equation: work done = force × distance moved in the direction of the force In symbols: 𝑊 =𝐹×𝑑 For example, if a 4 N force moves an object 3 m, the work done is 12 J. Energy Things have energy if they can be used to do work. A compressed spring has energy; so does the tank full of petrol. Like work, energy is measured in joules (J). Although people talk about energy being stored or given out, energy isn’t a ‘thing’. If, say, a compressed spring stores 100 joules of energy, this is just a measurement of how much work can be done by the spring. Energy can take different forms. To understand them, you need to know the following:
Moving objects have energy. For example, a moving ball can do work by knocking something over. Materials are made up of atoms (or group of atoms). These are constantly in motion. For example, in solid such as iron, the atoms are vibrating. If the solid is heated and its temperature rises, the atoms move faster. So the material has more energy when hot than when cold. (Pople, 2010, p. 78) 41
a. b. c. d.
What does the amount of mechanical work depend on? How does the article explain the term energy? Why does abject have more energy when it is hot than when cold? How would you explain the term energy to your students?
a.
b.
c.
d.
9. Look at the picture of a pendulum bellow. In which position has the bob the biggest potential energy? In which position does it have the biggest kinetic energy? Explain why.
Picture 14: Pendulum
42
10. There are two kinds of energy – potential and kinetic. Kinetic energy is associated with the movement of a body; potential energy is associated with its position, for example in the gravitational field of the Earth. There are two formulas for calculation of these two forms of energy. Describe all the components.
1 𝐸𝑘 = 𝑚𝑣 2 2
𝐸𝑝 = 𝑚𝑔ℎ
m g h v
11. There are several quantities and their units that are related to the concept of rigid body. Complete the table. Physical Quantity
Quantity Symbol
Unit
Unit Symbol
newton N·m energy W pascal
12. Look at the picture of the two types of pulleys below and answer the following questions.
Picture 15: Pulleys (Test Prep - Online, 2016)
43
a. Which of them is the fixed pulley and which of them the movable pulley? b. The load is the same in both cases. The gravitational force acting upon the load is 50 N. What force do you have to exert if you want to move the load using the fixed pulley and the movable pulley? c. Does the movable pulley decrease the amount of work that is needed to lift the load in comparison with the fixed pulley? d. What is a block and tackle? a.
b.
c.
d.
13. A diver stands on a diving platform and he is about to jump. The platform is 10 m above the water surface and the diver’s mass is 80 kg. What will be the kinetic energy of the falling diver just before hitting the water surface?
Picture 16: Diver
44
5. Liquids and Gases 1. Read the text and answer the following questions. apply cause dam dense particular
použít, uplatnit způsobit přehrada, hráz hustý konkrétní
shape stationary vessel width withstand
tvar stacionární plavidlo šířka vydržet, odolat
Pressure in Liquids A liquid is held in its container by its weight. This causes pressure on the container, and pressure on any object in the liquid. The following properties apply to any stationary liquid in an open container. Pressure acts in all directions The liquid pushes on every surface in contact with it, no matter which way the surface is facing. For example, the deep-sea vessel has to withstand the crushing effect of sea water pushing in on it from all sides, not just downwards. Pressure increases with depths The deeper into a liquid you go, the greater the weight of liquid above and the higher the pressure. Dams are made thicker at the bottom to withstand the higher pressure there. Pressure depends on the density of the liquid The more dense the liquid, the higher the pressure at any particular depth. Pressure does not depend on the shape of the container Whatever the shape or width the pressure at any particular depth is the same. Calculating the pressure in a liquid The container has a base area A. It is filled to a depth h with a liquid of density ρ (Greek letter ‘rho’). To calculate the pressure on the base due to liquid, you first need to know the weight of the liquid on it: volume of liquid = base area × depth = 𝐴ℎ mass of liquid = density × volume = 𝜌𝐴ℎ weight of liquid = mass × 𝑔 So: force on base = 𝜌𝑔𝐴ℎ This force is acting on an area A. So: pressure =
force 𝜌𝑔𝐴ℎ = = 𝜌𝑔ℎ area 𝐴
At the depth h in a liquid of density ρ: pressure = 𝜌𝑔ℎ (Pople, 2010, p. 64) 45
a. What law of physics says that pressure exerted anywhere in an incompressible fluid is transmitted equally in all directions? b. Pressure is exerted on every object submerged in a liquid. What does this pressure depend on? c. What kind of pressure does the formula pressure=ρgh stand for? d. Calculate the pressure that is exerted on a diver in 50 m below the water surface (ρ=1000 kg/m3, g=10 m/s2). Do I have to involve the atmospheric pressure (patm=101.3 kPa)? e. Create a task for your students where they would have to calculate the pressure in a liquid.
The deepest place on Earth is the Mariana Trench near Guam in Pacific Ocean. In a special submarine (bathyscaphe) you can descent to more than 10,900 m below the sea level. The machine must withstand the pressure of 10.9 MPa!
Picture 17: Bathyscaphe Trieste (U.S. Naval Historical Center, 1959)
a. b. c. d.
e.
2. There are two branches of physics dealing with mechanic of liquids – hydrostatics and hydrodynamics. There are some physical phenomena the box which are rather associated with either hydrostatic or hydrodynamic. Divide them into two sections. Bernoulli's equation buoyancy capillary action hydraulic lever
hydrostatic pressure laminar flow Pascal's principle surface tension
turbulent flow viscosity vortex waves
46
hydrostatics
hydrodynamics
3. The terms fluid and liquid are often used as synonyms but they are not. Decide which substances (all of them are at room temperature) are liquids and which fluids. Tick the right boxes. substance
liquid
fluid
water oxygen petrol sand methane
4. Look at the picture below. Are the pressures p1– p5 the same? Why? You can use the vocabulary in the box. container density
depend on depth
measure shape
Picture 18: Hydrostatic pressure (Werneuchen, 2008)
47
5. There is a cross section of a dam in the picture. The height of the dam in the picture is 58 m. Calculate the hydrostatic pressure at the bottom. Why are dams far thicker at the bottom than on the top?
Picture 19: Cross-section of a dam (British Dam Society, 2010)
6. Fill the gaps in the definition of Archimedes’s principle with the terms in the box. You might need to adjust them. displace
submerge
upward
Archimedes’s principle When a body is fully or partially _________ in a fluid, a buoyant force Fb from the surrounding fluid acts on the body. The force is directed ______ and has a magnitude equal to the weight mfg of the fluid that has been _________ by the body.
48
7. In the picture below there are three cubes of the same volume submerged in the water. The first of them will float, the second one will stay at rest and the third will sink.
Picture 20: Three cubes submerged in water (Inouye, 2016)
a. What forces do the letters B and G in the pictures stand for? b. Explain why the first cube tends to float and the last cube tends to sink. c. The volume of the cubes is the same. Density is the quantity that is important to floating or sinking. Explain why. d. What can be the cubes A and B made of? a.
b.
c.
d.
8. The experiment in the picture below demonstrates the effects of the atmospheric pressure. Describe what is needed to conduct the experiment and the principle of the experiment itself (the effect of the atmospheric pressure). You can use the terms in the box. air pressure hemispheres hold together
pull apart separate vacuum seal
vacuum pump
49
The experiment was first conducted by Otto von Guericke, a German scientist and major of Magdeburg in 1654. He used several pairs of horses to separate the hemispheres (unsuccessfully) to demonstrate the power of the atmospheric pressure to the royal court in Regensburg.
Picture 22: Magdeburg hemispheres (Gibbs, 2013) Picture 21: Magdeburg Hemispheres (JB Systems, Inc., 2011) (50)
9. Read the article about hydraulics and answer the following questions. increase lift up particle pass piston
zvýšit zvednout částice předat píst
plunger push down repair squash
píst (u stříkačky) stlačit opravit rozmáčknout
How do hydraulic machines work? Hydraulic machines use liquids to produce very large forces. A hydraulic jack is used to lift up a car so the mechanic can repair it. In a gas there is lots of space between the particles, so you can compress a gas. Hydraulic machines work because unlike a gas, you cannot squash a liquid – liquids are incompressible. The particles in a liquid are effectively touching each other, so liquids pass on any pressure applied to them.
50
Picture 23: Hydraulic machine made of syringes (National Fluid Power Association, 2015)
The two syringes connected together show how a hydraulic jack works. What will happen if you push down on plunger A? Plunger B will move up. The force that you apply when you push down on A produces pressure in the liquid. This pressure is passed through the liquid to B. It produces a force which pushes B up. Increasing the Force A hydraulic machine can be used to increase the size of the force.
Picture 24: Hydraulic machine
The diagram shows how a hydraulic jack works. Two metal pistons are connected by a tube of liquid. The pistons can move in and out of the cylinders like the plunger in a syringe. When the machine applies a force to piston A, piston B will go up. The jack allows the mechanic to lift the car. If you push down with a force of 10 N on piston A, as shown in the diagram, then a pressure is produced in the liquid that is passed through the liquid to piston B. Pressure =
force 10 N = = 0.5 N/cm2 area 20 cm2
The liquid transmits this same pressure to piston B. What is the force at B? Force = pressure × area = 0.5 N/cm2 × 400 cm2 = 200 N
51
The force has increased from 10 N at A to 200 N at B. Because B has a bigger area, the force that is produced at B is bigger: The area of piston B is 20 times bigger so the force is 20 times bigger. (Reynolds, 2013, p. 156) a. What is a hydraulic jack? Is there any other name for this device? b. What main property of liquids is used in hydraulics? c. How does a hydraulic machine increase the force? a.
b.
c.
10. In early 16th century an Italian physicist and mathematician Envangelista Torricelli performed the famous Torricelli’s experiment. Fill the gaps in the article about this experiment with the expressions from the box.
Picture 25: Torricellian experiment (Schott, 1664)
column descent
experiment observe
perform result
tube
52
Torricelli’s barometric experiment The extremely famous experiment of argento vivo (mercury), was _________ by Torricelli in the spring of 1644 in Florence. Torricelli filled a glass ____, open at one end, with mercury. Then, closing off the open end with a finger, he tipped the tube upside down and lowered it into a basin containing more mercury. He ________ that the column of mercury only descended partially, stopping at a height of around 76 cm. Torricelli was convinced that the space created by the _______ of the mercury in the tube was empty, and that what held up the ______ of mercury depended on the pressure that the air exerted on the mercury in the basin. In a letter to Michelangelo Ricci, 11th June, 1644, Torricelli declared that his __________ proved two fundamental concepts: that nature did not abhor the void, and that the air had weight. The _______ of the mercury experiment opened a period of revolutionary transformations and forced a fresh look at a doctrine which had been in force for centuries. (Institute and Museum of History of Science, 1999) 11. At the picture below you can see a device for measuring the atmospheric pressure. Calculate the height h which the water reaches in case that the atmospheric pressure is pa=101,3 kPa.
Picture 26: Barometer
53
6. Thermodynamics 1. Read the article and answer the questions exactly heat up mercury narrow
přesně zahřát rtuť úzký
property record tube
vlastnost zaznamenat trubice
Hot and Cold The Difference between Energy and Temperature The temperature tells us how hot or cold something is. We use a thermometer to measure temperature. A liquid inside a very narrow glass tube expands when it is heated. For a long time thermometers were made using liquid mercury. Mercury is poisonous so today the liquid used in thermometers is alcohol. Digital thermometers do not use a liquid – instead they use a sensor to measure the temperature. We measure temperature in degrees Celsius (°C). Human body temperature is 37 °C. The coldest temperature ever recorded on Earth was -89.2 °C, in Antarctica in 1983. The hottest temperature ever recorded was 56.7 °C in Death Valley, USA in 1913. When we heat up a substance such as water, its temperature rises. We transfer energy from chemical store of a fuel such as gas to the thermal store of energy in the water. Thermal energy and temperature are not the same. A cup of warm water and a swimming pool can have exactly the same temperature. However; the swimming pool stores much more thermal energy than the water in the cup. Unlike thermal energy, temperature does not depend on the amount of the material. Heating Solids, Liquids, and Gases The process of heating changes the motion of particles. If you heat a solid the particles in the solid vibrate more. In liquids and gases the particles move faster. The temperature has increased. You cannot say that the individual particles in a solid, liquid, or gas get hotter. Each particle can only move or vibrate faster. The temperature of a solid is a property of the solid, not of the individual atoms or molecules that make up the solid. How much energy does it take to raise the temperature of an object? It depends on three things. (Reynolds, 2013, p. 204) a. The mass of the object. In a greater mass there are more particles. You need to transfer more energy to get them all moving or vibrating faster. b. What it is made of. The particles in different materials have different masses. If the particles are more massive you need more energy to get them moving or vibrating faster. c. The temperature change that you want. For a bigger temperature change you need to get the particles all moving or vibrating even faster. This takes more energy.
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a. How does the liquid thermometer work? What liquids are used in thermometers? b. In what units do we measure temperature? c. We have two cups of water - the same amount and temperature. If we pour it together, what happens with the thermal energy and the temperature of the mixture? We assume that during the mixing the liquid did not lose any of its thermal energy. d. If you want to raise the temperature of an object you must provide energy. The energy that is needed to heat up an object is dependent on three things. What are they?
Not only in relation with thermodynamics, we speak of extensive and intensive physical properties (or quantities). Intensive properties – the property does not change with the amount of substance. E.g. temperature, density Extensive properties – the property change with the amount of substance. E.g. thermal energy, volume, mass.
2. As we learned from the article, the temperature is a result of the movement of particles inside a matter. There are three pictures below. Match them with the right titles. For each of the states, describe the movement of the particles inside. Use the expressions in the box. fixed positions freely
change positions move about
particles vibrate
solid/solid state
liquid/liquid state gas/gaseous state Picture 27: Three states of matter (University of Waikato, 2010)
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3. Every matter can occur in three states. Every process of changing the state has its specific name. In the picture below fill in the missing states of matter and names of changes.
Picture 28: States of matter
4. Fill in the blanks in the text with the expressions from the box. cool dry ice
increase liquid
melting solid
sublime temperature
Condensation As gas _____, its particles move more slowly and the forces between them grow stronger. The gas then condenses to a ______. Condensation occurs at or below the substance’s boiling point. Oxygen, for example, condenses at -183 °C. It condenses at higher ___________ if the pressure on it is _________. Sublimation Some solids _______ when they are heated. This means that they change directly to a gas without first _______ and becoming liquid. An example is solid carbon dioxide, which is also called ___ ___. When cooled, the gas turns right back to a _____.
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5. Read the article and answer the following questions. burst escape humid increase invisible
prasknout uniknout vlhký zvýšit neviditelný
puddle reduce release skin vanish
kaluž snížit, omezit uvolnit kůže zmizet
Liquids and Vapours Evaporation Even on a cool day, rain puddles can vanish and wet clothes dry out. The water becomes an invisible gas (called vapour) which drifts away in the air. When a liquid below its boiling point changes into a gas, this is called evaporation. It happens because some particles in the liquid move faster than others. The faster ones near the surface have enough energy to escape and form the gas. These are several ways of making a liquid evaporate more quickly: Increase the temperature Wet clothes dry faster on a warm day because more of the particles (water molecules) have enough energy to escape. Increase the surface area Water in a puddle dries out more quickly than water in a cup because more of its molecules are close to the surface. Reduce humidity If air is very humid, this means that it already has high vapour content. In humid air, wet washing dries slowly because molecules in the vapour return to the liquid almost as fast as those in the liquid escape. In less humid air, wet washing dries more quickly. Blow air across the surface Wet clothes dry faster on a windy day because the moving air carries escaping water molecules away before many of them can return to the liquid. Boiling Boiling is a very rapid form of evaporation. When water boils, vapour bubbles form deep in the liquid. They expand, rise, burst, and release large amount of vapour. Even cold water has tiny vapour bubbles in it, but these are squashed by the pressure of the atmosphere. At 100 °C, the vapour pressure in the bubbles is strong enough to overcome atmospheric pressure, so the bubbles start to expand and boiling occurs. At the top of Mount Everest, where atmospheric pressure is less, water would boil at only 70 °C. The Cooling Effect of Evaporation Evaporation has a cooling effect. For example, if you wet your hands, the water on them starts to evaporate. As it evaporates, it takes thermal energy away from your skin. So your hands feel cold. The kinetic theory explains the cooling effect like this. If faster particles escape from the liquid, slower ones are left behind, so the temperature or the liquid is less than before. (Pople, 2010, p. 114) a. How can you increase evaporation? b. Why is the boiling temperature of water lower than 100 °C on Mount Everest? c. Evaporation has a cooling effect. Can you explain why? Explain why people sweat in hot weather. 57
d. What experiments or real life examples would you use in your lessons to demonstrate evaporation, boiling or the cooling effect of evaporation? a.
b.
c.
d.
6. One of the ways of heat transmission is thermal radiation. Hot bodies emit infrared waves and they consequently heat up other objects. So does our Sun. One of the hot issues nowadays is the greenhouse effect. Can you describe it? Use the parts of the sentences in the box. escape by rising and flowing away ground warms up heat the air
hot air is trapped radiation passes through easily
Picture 29: Greenhouse effect (BioNinja, 2016)
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7. Match the terms with their definitions. contraction heat radiation thermal insulator
expansion thermal conduction
heat thermal convection
a material that resists the flow of heat a shrinking in size when something gets colder an increase in size when something gets hotter the flow of heat in the form of infrared rays, which do not need a material or medium to transfer heat the flow of heat through a fluid the flow of heat through a solid the kind of energy that makes things hot or cold
8. Match the parts of the vacuum flask with the terms in the box. Explain how such a vacuum flask works and answer the following questions. casting silver coating double walled metal or glass container
vacuum stopper
Picture 30: Internal structure of a vacuum flask (Physics World, 2006)
Think about thermal conduction, convection and heat radiation. Why there is the silver coating? Give examples of good thermal conductors and insulators.
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9. There is a four-stroke spark-ignition engine. Match the phases of its working cycle with the pictures. compression
intake
exhaust
expansion
Picture 31: Four-stroke spark-ignition engine (Leduc, 2016)
10. There are three temperature scales in use today, Fahrenheit, Celsius and Kelvin. Read the following two paragraphs and decide which of the temperature scales they describe. __________ temperature scale is a scale based on 32 for the freezing point of water and 212 for the boiling point of water, the interval between the two being divided into 180 parts. The 18th-century German physicist Daniel Gabriel __________ originally took as the zero of his scale the temperature of an equal ice-salt mixture and selected the values of 30 and 90 for the freezing point of water and normal body temperature, respectively; these later were revised to 32 and 96, but the final scale required an adjustment to 98.6 for the latter value. Until the 1970s the __________ temperature scale was in general common use in English-speaking countries; the Celsius, or centigrade, scale was employed in most other countries and for scientific purposes worldwide. Since that time, however, most English-speaking countries have officially adopted the Celsius scale. The conversion formula for a temperature that is expressed on the Celsius (C) scale to its __________ (_) representation is: 60
9 _ = 𝐶 + 32 5 ______ temperature scale is the base unit of thermodynamic temperature measurement in the International System (SI) of measurement. It is defined as 1/ 273.16 of the triple point (equilibrium among the solid, liquid, and gaseous phases) of pure water. The ______ (symbol _ without the degree sign [°]) is also the fundamental unit of the Kelvin scale, an absolute temperature scale named for the British physicist William Thomson, Baron ______. Such a scale has as its zero point absolute zero, the theoretical temperature at which the molecules of a substance have the lowest energy. Many physical laws and formulas can be expressed more simply when an absolute temperature scale is used; accordingly, the ______ scale has been adopted as the international standard for scientific temperature measurement. The ______scale is related to the Celsius scale. The difference between the freezing and boiling points of water is 100 degrees in each, so that the ______ has the same magnitude as the degree Celsius. 11. After reading the article, fill in the temperatures that are missing.
Picture 32: Temperature scales (Pearson Prentice Hall, Inc., 2010)
12. There is a pot full of water (5l) heating up on the cooker. The water originally had 25 °C and it is boiling at the moment. How much heat did the water accept? cwater=4,200 J/(kg°C)
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7. Electricity 1. Read the article and answer the following questions. attract crackle like overall Perspex repel
přitahovat praskat souhlasné celkový typ plastu odpuzovat
rod rub spark suggest unlike
tyč třít jiskra naznačit, navrhnout nesouhlasné
Electric charge Electric charge, or ‘electricity’, can come from batteries and generators. But some materials become charged when they are rubbed. Their charge is sometimes called electrostatic charge or ‘static electricity’. It causes sparks and crackles when you take off a pullover, and if you slide out of a car seat and touch the door, it may even give you a shock. Negative and positive charges Polythene and Perspex can be charged by rubbing them with a dry, woollen cloth. When two charged polythene rods are brought close together they repel each other (try to push each other apart). The same thing happens with two charged Perspex rods. However, a charged polythene rod and a charged Perspex rod attract each other. Experiments like this suggest that there are two different and opposite types of electric charge. These are called positive (+) and negative (-) charge. Like charges repel; unlike charges attract. The closer the charges, the greater the force between them. Where the charge comes from Everything is made of tiny particles called atoms. These have electric charges inside them. There is a central nucleus made up of protons and neutrons. Orbiting the nucleus are much lighter electrons: Electrons have a negative (-) charge. Protons have an equal positive (+) charge. Neutrons have no charge. Normally, atoms have equal numbers of electrons and protons, so the net (overall) charge on a material is zero. However, when two materials are rubbed together, electrons may be transferred from one to the other. One material ends up with more electrons than normal and the other with less. So one has a net negative charge, while the other is left with a net positive charge. Rubbing materials together does not make electric charge. It just separates charges that are already there. (Pople, 2010, p. 170)
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a. What causes sparks and crackles when you take off a pullover? b. How do you make a plastic rod become charged? c. How does the force between the charges change with the change of the distance between them? d. What does an atom consist of? e. The experiment with the charged rods is used for demonstrating static electricity. Think about another similar experiment and describe it in a few sentences. a.
b.
c.
d.
e.
2. Complete the description of a leaf electroscope.
Picture 33: Leaf electroscope (Enter to Learn, 2011)
gold leaf charge
metal plate object
repel rise
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Electric ______ can be detected using a leaf electroscope as above. If a charged ______ is placed near the ____________, charges are induced in the electroscope. Those in the _________ and metal stem ____, so the leaf ____.
3. Complete the table with physical quantities that are related to electricity.
Physical Quantity
Quantity Symbol
Unit
Unit Symbol
electric charge
Measuring Instrument
C
I
ammeter
potential difference, voltage
volt
R
Ω
watt
energy
wattmeter
J, kWh
4. Match the terms and their definition electric field direct current (DC)
electric current alternating current (AC)
electrostatic induction resistance
the way in which a charged object produces an electric charge in another object the degree to which a substance resists electric current a substance through which electricity can flow electric current in which electrons flow in one direction only the flow of electric charge through a substance the area around a charged object in which it exerts a force electric current in which electrons change direction many times per second (5) 64
5. Fill the gaps in the articles about electrical conductors and insulators. conduction conductor
covering insulator
metal plastic
safe
Electrical _________ – a substance through which electricity can flow Most ______ are good electrical conductors. Their atoms have free electrons that move easily. The passage of electricity through a substance is called electrical __________. Electrical _________ – substance that blocks the flow of electricity An insulator does not conduct electricity because its atoms have no free electrons. _______ and ceramics are good insulators. Insulation is the use of insulators to make electrical device ____ to handle. The _________ on wires and electrical components are made from insulators. (Tulajová, 2000, p. 107) 6. Give 5 examples of conductors and 5 examples of insulators insulators:
conductors:
7. There are two electrical circuits. Look at them and answer the questions bellow.
Picture 35: Series and parallel circuits
a. Which of the circuit components are present in the circuits? Which other components used for building circuits do you know? b. In which circuit are the bulbs connected in series? Which is a parallel connection? c. What happens when one of the bulbs in each circuit is removed? Will the other still glow or will it go out? d. All four bulbs are identical and also the power sources are the same. Explain why the bulbs glow dimmer when they are
In the late 1880s two famous physicists – Nikola Tesla and Thomas Edison were involved in a battle called War of Currents. Tesla believed in alternating current whereas Edison was promoting direct current and led the smearing campaign against Tesla. The first milestone in this battle was electrification Chicago’s World Fair using AC in 1893. The second success of AC came in 1886 when the Niagara Falls Power Company started power Buffalo. Tesla’s AC has won!
Picture 34: Nikola Tesla (Sarony, 1893)
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connected in series that when they are connected in parallel. a.
b.
c.
d.
8. Read the article about ohmic and non-ohmic behaviour and then write what Ohm’s law says about current and potential difference. Use the vocabulary in the box.
Picture 36: Ohmic and non-ohmic behaviour (Kirk, 2014, p. 55)
If current and potential difference are proportional (like the metal at constant temperature) the device is said to be ohmic. Devices where current and potential difference are not proportional (like the filament lamp or the diode) are said to be non-ohmic. (Kirk, 2014, p. 55) a piece of metal constant
current potential difference
proportional to temperature
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Ohm’s law
9. Read the article about power and answer the following questions. appliance bill convert give out
zařízení účet převést, přeměnit vydávat
lighthouse rate supplier torch
maják míra, tempo dodavatel svítilna
Power Some lamps are brighter than others. The lamp in the lighthouse is much, much brighter than the lamps used in torches or in houses or offices. An electric current transfers energy from the mains supply to the lamp in the lighthouse. The lamp changes this energy into light energy and thermal energy. A bright lamp gives out lots of light energy each second. It converts the energy from the mains supply into light energy faster. The rate at which energy is converted is called the power. Power is measured in watts (W) or kilowatts (kW). 1 kW = 1000 W. You can calculate power using an equation: Power (W) =
energy transferred (J) time taken (s)
Not only plugs and sockets differ all around the world. For example the residential voltage (voltage that is in sockets in your house) in the Czech Republic is 230 V. It is the same in UK but it is only 120 V in the USA. Below you can see the plug and socket used in the USA
The lighthouse lamp changes 2400 J of energy into light and thermal energy each minute. The lamp in a torch changes the chemical energy in a battery into light and thermal energy. It transfers energy more slowly than the lighthouse lamp so the power is much less. The torch lamp transfers energy at a rate of 120 J each minute.
Picture 37: Plug and socket type B (World Standards, 2016) and in the UK.
To calculate the power you have to convert the time to seconds. For the lighthouse: Power =
24 000 J = 400 𝑊 60 s
For the torch: 120 J = 20 𝑊 60 s A lighthouse is 20 times more powerful than a torch lamp.
Picture 38: Plug and socket type G (World Standards, 2016)
Power =
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Energy and money When people pay their electricity bill they pay for energy, not current or voltage. The electricity supplier works out how much energy they have used. It depends on the power of their appliances and how long they are used for: Energy (J) = power (W) × time(s) People use lots and lots of joules of energy each month. So instead the energy is measured in a different unit, the kilowatt-hour (kWh). Energy (kWh) = power (kW) × time(h) For example, if you use a 10 w (0.01 kW) Led for 10 hours in one month, the energy that you would pay for would be: Energy = 0.01 kW × 10 h = 0.1 kWh To produce the same amount of light using a normal light bulb you would need to use a 60 w light bulb. You would pay for 0.6 kWh instead. Using new light bulbs can save a lot of money. LEDs are a lot more expensive to purchase than incandescent or CFL light bulbs, but they do last a long time. (Reynolds, 2013, p. 200) a. How do you define power? b. We do not pay for the electricity we use in joules because it is quite a small unit. Instead we use kilowatt-hours. How many joules is one kilowatt-hour? a.
b.
10. In the following table you can see different types of bulbs and their power for certain intensity of light. Match the types of light bulbs with the pictures and answer the following questions.
Picture 39: Bulbs (Locations North, 2016)
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Light intensity (lumens) 450 800 1400 1800 2800
Power of incandescent light bulb (W) 40 60 75 100 150
Power of CFL (energy-saving-lamp) (W) 10 15 20 25 45
Power of LED lamp (W) 7.5 10 14 18 26
a. Which of the light bulbs is the most efficient and why? Think of the transformation of energy. b. In the Czech Republic the cost of 1 kWh is roughly 5 CZK. How much would you pay in a year if you used an old-fashioned incandescent light bulb and if you use a LED lamp? The light must be on 8 hours a day, 5 days a week. c. Do you know what CFL means? a.
b.
c.
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8. Magnetism 1. Read the article and answer the questions. direction exert include invisible line up
směr působit zahrnovat neviditelný seřadit
loop make up pull push
stáčet se, smyčka skládat táhnout tlačit
Magnetism Magnets and electric currents exert an invisible force on iron objects and other magnets. This force is magnetism. The Earth itself is a giant magnet with two magnetic poles. Electromagnets are formed by electric currents. They are used in machines such as cars, computers and television sets. Magnet A magnet attracts iron and some other materials and attracts or repels other magnets within its magnetic field. If it is free to move, a magnet turns to line up with the Earth’s magnetic field. Only certain materials are magnetic. These include some metals, such as iron, nickel, and cobalt, some alloys, and some ceramics. Lodestone is a magnetic mineral made of iron oxide. A permanent magnet is always magnetic, but a temporary magnet can gain and lose its magnetic force. A keeper is a bar of iron that you place on a permanent magnet to help keep its magnetism when you are not using it. Magnetic field A magnet only attracts objects when they are within its magnetic field. Two magnets push or pull on each other if their magnetic fields come together. At each point in the field, the magnet exerts a force in a certain direction. These directions follow lines of force or flux, which loops around the magnet from one pole to the other. A wire carrying an electric current is also surrounded by a magnetic field, while the current is flowing. Magnetic pole A magnet has two poles called the north pole and the south pole. The magnetic force is strongest at each pole. Opposite poles attract, so a north pole attracts a south pole. But like poles repel, and two magnets placed north to north pole will push each other away. Domain A magnetic material, such as iron or steel, is made up of many tiny regions of magnetism, called domains. These are magnetic because the atoms inside them behave like miniature magnets. The moving electric charges of spinning electrons in the atoms produce magnetic fields. In a domain, the atoms line up in the same direction to form two magnetic fields. In a domain, the atoms line up in the same direction to form two magnetic poles. Normally, the poles of different domains point in different directions, so there is no overall magnetism. An 70
outside magnetic field makes the poles of the domains line up in the same direction. This magnetizes the material, and it becomes a magnet. (Tulajová, 2000, p. 103) a. b. c. d.
Which objects exert the magnetic force? What happens when a magnet is placed into the magnetic field of another magnet? How does a magnet that is free to move line up in the magnetic field of the Earth? What is a magnetic domain?
a.
b.
c.
d.
2. Connect the following terms with their definitions. magnetic field magnetic induction
magnetic pole electromagnet
domain magnetic field lines
lines that help us to visualize a magnetic field the area around the magnet in which it exerts force a form of a magnet that works by electricity a small magnetic area in a magnetic material one of the two points in a magnet where its magnetism is the strongest the production of magnetism in another object by a magnet
3. Draw a simplified diagram of the magnetic field pattern of a bar magnet. Describe the direction of the magnetic field using the vocabulary below.
Picture 40: Bar magnet
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curve magnetic field lines
pole return
spread out
4. State where in the picture you can find the geographical North and South poles and where the magnetic North and South poles. Explain the term magnetic declination.
Picture 41: The Earth's magnetic field (Brashford, 1990)
5. Fill the gaps in the article about electromagnets. Use the expressions in the box. You might change them a bit. coil magnetize turn
core permanently wire
current steel
direction temporary
Electromagnets Unlike an ordinary magnet, an electromagnet can be switched on and off. In a simple electromagnet, a ____, consisting of several hundred turns of insulated copper ____, is wound round a core, usually of iron or Mumetal. When a _______ flows through the coil, it produces a magnetic field. This __________ the core, creating a magnetic field about a thousand times stronger than the coil by itself. With an iron or Mumetal core, the magnetism is only _________, and is lost as soon as the current through the coil is switched off. _____ would not be suitable as a core because it would become ___________ magnetized. 72
The strength of the magnetic field is increased by:
increasing current increasing number of _____ in the coil
Reversing the current reverses the _________ of the magnetic field. (Pople, 2010, p. 208) 6. Read about the right-hand grip rule. Right-hand grip rule The direction of the magnetic field produced by a current is given by the right-hand grip rule. If you grip the wire with the right hand so that the thumb points in the current direction the fingers point in the same direction as the magnetic field lines. In the similar way describe the Fleming’s left hand rule. Use the vocabulary in the box.
Picture 43: Fleming's left hand rule (Electrical4u, 2016)
hold index finger middle finger
držet ukazováček prostředníček
point right angle thumb
In Czech textbooks of physics the Fleming’s lefthand rule is described as follows: If you place your palm onto a conductor so the fingers show the direction of the electric current and magnetic field lines enter your palm, then your thumb will show the direction of the magnetic force.
Picture 42: Fleming's left hand rule 2
ukazovat, směřovat pravý úhel palec
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7. Look at the picture of an electric motor and fill the gaps with the terms from the box. Then read the article and fill the gaps in it. brushes
coil
commutator (split ring)
magnet
Picture 44: Simple DC motor (Hasselo, 2016)
A simple DC motor The diagram above shows a simple electric motor: It runs on direct current (DC), the ‘one-way’ current that flows from battery. The coil is made of insulated copper wire. It is free to rotate between the poles of the magnet. The commutator, or the split ring, is fixed to the coil and rotates with it. The brushes are two contacts which rub against the commutator and keep the coil connected to the battery. They are usually made of carbon. When the coil is horizontal, the forces are the furthest apart and have their maximum turning effect (leverage) on the coil. With no change to the forces, the coil would eventually come to rest in the vertical position. However, as the coil overshoots the vertical, the commutator changes the direction of the current through it. So the forces change direction and push the coil further round until it is again vertical... and so on. In this way, the coil keeps rotating clockwise, half a turn at a time. If either the battery or the poles of the magnet were the other way round, the coil would rotate anticlockwise. The turning effect on the coil can be increased by:
increasing the _______ using a stronger ______ increasing the number of _____ __ ___ ____ increasing the ____off the coil. (A longer coil means higher forces because there is a greater length of wire in the magnetic field; a wider coil gives the forces more leverage.) (Pople, 2010, p. 212) 74
8. Electric bell is another device using an electromagnet. There are sentences describing its principle. Put them in order.
Picture 45: Electric bell (BBC, 2014)
This breaks the circuit, the contacts no longer touch each other, and the core is no longer magnetised. The sequence starts again so the bell keeps ringing for as long as the bell-switch is pressed. The striker is attracted to the core and hits the bell producing a sound. The striker springs back and completes the circuit again. Someone presses the bell switch thus the circle is complete. A current passes through the coil and the iron core is magnetised.
9. Read the article about the Maglev train and answer the following questions. condition guidance introduce keep
podmínka vedení, vodící představit, uvést udržet, nechat
possible property under development
možný vlastnost ve vývoji
Maglev The Maglev Train is still under development and many scientists are working on the project. The basic idea is to use magnets to power the train; however, it’s not yet possible to make the magnetic repulsion constant. Figure 1 shows the sides of the magnets are repelling each other and one is repelling another into the air, which makes them levitate. But that’s just under ideal conditions. In reality, the one on the top of the magnet will fall down to the side. So many different ideas have come out to figure out this problem. 75
Picture 46: Repelling magnets (Jeon, 2016)
EMS Figure 2 shows a system that was introduced by a German scientist. Its system is called Transrapid. This design uses EMS technology. EMS is also known as Electromagnetic suspension. EMS systems use the attractive property of magnets as shown in figure 2. Since the same pole of magnets are attracted to each other, the stator and support magnets are attracted to each other in figure 2. It causes the train to not land on the track. It adjusts the power of the magnetic field produced by electromagnets that levitate an object into the air. As shown in figure 2, there is a guidance magnet on the side of the track that generates the magnetic force that prevents the train from moving side to side. It also designed as the C-form to keep the train in the bounce. As you can see in the picture, the train cannot touch any side of the track levitating in the air because of the magnetic force pushing the train to the middle.
Picture 47: EMS system (Jeon, 2016)
EDS EDS stands for Electrodynamics suspension. As the maglev train travels at high speeds through the coils, superconducting magnets on the side of the train induce the current from the coils. A magnetic field is generated as shown in the picture on top of figure 4. The EDS system works as an opposing pole for the magnetic field on the front of the train, this way the train can move without any other force while the train is levitating on the track. The magnetic field on the back of the train will change to the same pole of the magnetic field on the train which pushes the train. Now the train has no friction levitating on the track with a magnetic system that makes it goes smooth and fast. The picture on the bottom of figure 4 shows this demonstration. (Jeon, 2016) 76
Picture 48: EDS system (Jeon, 2016)
a. b. c. d.
What properties of magnets does the Maglev train use? Does it use permanent magnets? EMS system moves the train forwards. Is this statement true? If not, why? Describe the principle of the EDS system in your own words. Think about an experiment that you would show to your students to demonstrate the mechanism of the Maglev train.
a.
b.
c.
d.
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9. Waves and Sound 1. Read the article and answer the following questions. bounce up/down coil
poskakovat, odrazit loudspeaker se nahoru/dolu smyčka loudspeaker cone
disturbance drumskin gas layer liquid
vzruch, nepokoj blána bubnu plynný, plyn vrstva tekutý, tekutina
pass on Slinky spring solid vocal chords
reproduktor membrána reproduktoru posunout, předat pružina (hračka) pevný, pevná látka hlasivky
Making sounds Your vocal chords, a drumskin, and a loudspeaker cone are all examples of things that vibrate to produce sound. Sound transfers energy from a source such as a drum to a detector such as your ear. Sound needs a material, or medium, to travel through, such as air, water, or walls. The vibrating sound produces a disturbance in the medium. This disturbance travels from the source to your ear, and that is when you hear the sound. You can hear sounds when you are underwater. Animals such as dolphins and whales communicate over very large distances by making and hearing sounds. If someone is talking loudly in the next room you will probably hear them, because sound travels through solid materials like walls. Sound cannot travel through empty space. A space that is completely empty of everything, including air, is a vacuum. What is a sound wave? If you put small polystyrene balls on a loud speaker cone, they will bounce up and down, showing that the cone is vibrating. The cone moves out, than back, then out again. The vibrating loudspeaker cone makes the air molecules next to it move backwards and forwards. This disturbance, or vibration, is what we call a sound wave. The layer of air next to the loudspeaker vibrates, which makes the next layer of air molecules vibrate, and so on. In this way a sound wave moves through the air. The air itself does not move away from the cone. The sound wave transfers energy through the motion of the air molecules, and the wave moves from the loudspeaker out to your ear. You cannot see the air molecules moving but you can make model of a sound wave using a Slinky spring. If you hold the end and move your hand forwards and backwards, the coils move closer together then further apart as the wave moves along the Slinky. The individual coils do not travel to the end of the Slinky, but the wave does.
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The speed of sound Sound waves travel at different speeds in solids, liquids, and gasses. They travel fastest in solids and the slowest in gasses. This is because the particles in a solid are closer together than they are in a gas, so the vibration is passed on more quickly. (Reynolds, 2013, p. 94) a. What a thing has to do to produce sound? state some examples of things that produce sounds b. Can sound travel through empty space? Why? c. Describe production and propagation of a sound wave. d. What can be used for demonstration of a sound wave? e. What does the speed of sound depend on?
The speed of sound in dry air at 20 °C is 343.2 m/s (1,236. km/h). In water it is 1481 m/s and in iron it is 5130 m/s. In aerodynamics the speed of sound is used for assessing speeds of aircrafts. Mach number (M) is the ratio of velocity (of an object, v) to the speed of sound (c). 𝑀=
𝑢 𝑐
Thus we can divide aircrafts to: subsonic (M<1) supersonic (5>M>1) hypersonic (5<M)
a.
b.
c.
d.
e.
2. Match the following terms with their definitions. amplitude
frequency
period
wavelength
The distance between the two consecutive corresponding points with the same phase. The maximum displacement from the mean position. The number of waves passing any point per second. The time taken for one complete oscillation, i.e. the time taken for one complete wave to pass any given point.
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3. Fill the gaps in the article about electromagnetic waves. Use the words from the box. angle energy lose
nucleus radiation space
space strike
Electromagnetic wave Light and other forms of electromagnetic _________ travel as waves. The wave is produced when, for example, an electron in an atom _____ energy and jumps to a lower orbit, or energy level, around atom’s _______. This sets off a vibration of electrical energy that travels outward through _____ in the form of electric and magnetic fields. These fields are at right ______ to each other, and to the direction of travel of the wave. When the electromagnetic wave _______ another atom, the fields can cause an electron to jump and gain energy. In this way, an electromagnetic wave carries ______ through space. (Tulajová, 2000, p.76)
4. When an electric bell is placed into space where there is no air (almost vacuum), the bell goes quiet and observer hears nothing. Explain why the observer hears no sound even though the bell is ringing.
Picture 49: Bell jar experiment (Excellup, 2014)
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5. Loudness of sound can be measured in so-called decibels (dB). The physical quantity is called sound pressure level Lp. Match the different sounds with the right values of sound pressure level. rustling leaves in distance disco, 1 m from the speaker
conversational speech, 1m busy road, 5 m away away threshold of pain
Lp (dB)
sound/noise
140
Jet aircraft, 50 m away
Do you know why you can’t hear a dog whistle? It’s because we have different hearing range from dogs – we can hear different range of frequencies.
130
100 80 60
A gradual loss of sensitivity to higher frequencies is considered normal. That’s why you can’t hear higher frequencies when you get older.
10 0
humans: 20 – 20,000 Hz dogs: 64 – 44,000 Hz elephants: 17 – 10,500 Hz dolphins: 150 – 150,000 Hz
hearing threshold
6. Read the article about types of waves and answer the following questions. angle density parallel particle result from
úhel hustota kolmý částice je výsledkem
string successive surface taut velocity
struna, provázek po sobě jdoucí povrch napnutý rychlost
Types of waves Waves are divided into types according to the direction of the displacements in relation to the direction of the motion of the wave itself. If the vibration is parallel to the direction of motion, the wave is known as a longitudinal wave. The longitudinal wave is always mechanical because it results from successive compressions (state of maximum density and pressure) of the medium. Sound waves typify this form of wave motion. Another type of wave is a transverse wave, in which the vibrations are at right angles to the direction of motion. A transverse wave can be mechanical, such as the wave projected in a taut string that is subjected to a transverse vibration; or it may be electromagnetic, such as light, x-ray, or radio waves. Some mechanical wave motions, such as waves on the surface of a liquid, are combinations of both longitudinal and transverse motions, resulting in the circular motion of liquid particles. For transverse wave, the wavelength is the distance between two successive crests or troughs. For longitudinal waves, it is the distance from compression to compression or rarefaction to rarefaction. The frequency of the wave is the number of vibrations per second. The velocity of 81
the wave, which is the speed at which it advances, is equal to the wavelength times the frequency. The maximum displacement involved in the vibration is called the amplitude of the wave. (Tulajová, 2000, p. 77) a. b. c. d.
Why are the longitudinal waves always mechanical? What type of wave is a sound wave? How would you explain the term wavelength? What is the term used for the maximum displacement involved in the vibration?
a.
b.
c.
d.
7. The motion of a wave involves a transfer of energy. Match the types of waves with the examples of energy transfer. compression waves down a light waves spring earthquake waves sound waves
Wave
water ripples waves along a stretched rope
Example of energy transfer. A floating object gains an ‘up and down’ motion. The sound received at an ear makes eardrum vibrate. The back of the eye (the retina) is stimulated when light is received. Building collapse during an earthquake. A ‘sideways pulse’ will travel down a rope that is held taut between two people. A compression pulse will travel down a spring that is held taut between two people (Kirk, 2014, p. 35)
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10. Optics and Light 1. Read the article about light and answer the following questions. block out blurred corner edge fuzzy
zakrýt, nevpustit neostrý, rozmazaný roh okraj, hrana neostrý, střapatý
reach sharp source straight transfer
dosáhnout ostrý zdroj přímý přenášet
Light transfers energy Light is a way of transferring energy. Light sources give out light. We say they are luminous. Energy transferred from the Sun to the Earth by light waves. Light can reach us from the Sun and other stars. It can travel through empty space because unlike sound, light does not need a medium to travel through. Infrared radiation, called heat or thermal energy, is very similar to light and is another method by which energy reaches us from the Sun. Shadows Shadows are dark areas where something blocks out light. They are formed because light travels in straight lines and does not bend around corners, so if something is in its path the light is blocked. On a sunny day you can look down and see your shadow on the ground. The light from the Sun cannot pass through you because you are opaque and block out the light. Sometime shadows have fuzzy edges and sometimes they have sharp edges. It depends on the type of light source. If the light source is small, there is a full shadow called an umbra and the edges of the shadow are sharp. If the light source is large or spread out, there is a partial shadow called a penumbra as well as an umbra and the edges of the shadow appear blurred. (Reynolds, 2013, p. 110) a. b. c. d.
What objects are luminous? Give examples. What medium does light need for its propagation? Explain the term opaque. What the opposite word? What is the difference between umbra and penumbra?
a.
b.
c.
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d.
2. Describe the human eye. Use the terms in the box. sclera iris
optic nerve pupil/lens
vitreous body cornea
retina
Picture 50: Human eye (Sherafat, 2016)
3. Complete the article with the terms in the box. converge distant
focusing retina
spectacles thick
With many people, changes in the shape of the eye lens are not enough to produce sharp ________ on retina. To overcome the problem, _________ or contact lenses have to be worn. Short sight In a short-sighted eye, the lens cannot be made thin enough for looking at _______ objects. So the rays are bent inwards too much. They ________ before they reach retina. Long sight In a long-sighted eye, the lens cannot be made _____ enough for looking at close objects. So the rays are not bent inwards enough. When they reach the ______, they have still not met. (Pople, 2010, p. 158) 4. What types of lenses are used to correct these faults? Short sight
Long sight
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What glasses (what type of lens) would you use to use to ignite fire?
5. We can draw a so called ray diagrams to predict the size and position of the image formed by a lens. Match the terms in the box with the corresponding parts of the ray diagram. object real focal point
image principal axis
virtual focal point converging lens
Picture 51: Ray diagram of a converging lens
a. There are three rays used in a ray diagram and they are called standard rays. Match the numbers of the rays from the diagram above with their descriptions. The ray through the centre passes straight through the lens. The ray parallel to the principal axis passes through the virtual focal point (focus) after leaving the lens. The ray through the real focal point (focus) leaves the lens parallel to the principal axis.
b. What are the properties of the image in the diagram? Cross out the wrong ones. real
X virtual
upright
X inverted
larger than X smaller than object object 85
c. Look at the ray diagram of a concave (diverging) lens, describe the paths of the rays in the picture and the properties of the resulting image.
Picture 52: Ray diagram of a diverging lens
6. Fill in the gaps in the article about a compound microscope. eyepiece image
magnification magnified
object real
Compound microscope A compound microscope consists of two lenses – the objective lens and the ________ lens. The first lens (the objective lens) forms a real __________ image of the object being viewed. This real image can then be considered as the ______ for the second lens (the eyepiece lens) which acts as a magnifying lens. The rays from this ____ image travel into the eyepiece lens and they form a virtual magnified image. In normal adjustment, this virtual _____ is arranged to be located at the near point so that maximum angular _____________ is obtained. (Kirk, 2014, p. 179)
First optical microscopes appeared in 1620s in Netherlands. A huge impact on using microscopes had Antonie van Leeuwenhoek who discovered red blood cells in 1670s. In early 20th century an alternative to the light microscopes was developed – electron microscope which uses electrons to generate the image.
Picture 53: Binocular Laboratory Compound Microscope (Amscope, 2015)
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7. Look at the picture below and explain what happens when a beam of light hits a glass prism. You can use the vocabulary in the box. beam of light block of glass deviate
dispersion enter exit
normal prism range of colours
refract spectrum split
a. When a beam of white light is dispersed, which colours are present? b. Which of the colours of the visible spectrum has the highest frequency? Which of them has the longest wavelength? c. What experiments or natural phenomena would you use to demonstrate refraction to your students? a.
b.
c.
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8. Read the paragraph about reflection and do the following task. The laws of reflection When a ray of light strikes a mirror, it is reflected. The incoming ray is the incident ray, the outgoing ray is the reflected ray, and the line at right – angles to the mirror’s surface is called normal. The mirror in this case is a plane mirror. This just means that it is a flat mirror, rather than a curved one. There are two laws of reflection. They apply to all types of mirror: 1. The angle of incidence is equal to the angle of reflection. 2. The incident ray, the reflected ray, and the normal all lie in the same plane. Put another way, light is reflected at the same angle as it arrives. (Pople, 2010, p. 142) Based on the article, create two questions that can be used in a test for your students.
9. Look at the statements about forming an image by a plane mirror. Correct the wrong ones.
Picture 54: Plane mirror (TutorVista, 2016)
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The image is bigger than object.
The image is as far behind the mirror as the object is in front.
The image is upright.
The image is real.
10. There are two more types of mirrors – concave and convex mirrors. They can both be demonstrated using a simple spoon. Decide which of the surfaces is convex and which is concave.
Picture 55: Spoon (Applect Learning Systems Pvt. Ltd., 2015)
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11. Atomic Physics 1. Read the article and answer the following questions. depend on develop full-stop make up
záviset na vyvinout, vytvořit tečka vytvořit
ordinary surface virtually
A Simple Model of Atom Everything is made of atoms. Atoms are far too small to be seen with any ordinary microscope – there are more than billion billion of them on the surface of this full stop. However, by shooting tiny atomic particles through atoms, scientists have been able to develop models (descriptions) of their structure. In advanced work, scientists use a mathematical model of the atom. However, the simple model is often used to explain the basic ideas.
Picture 57: Carbon atom (Goffey, 2010)
běžný povrch prakticky, v podstatě
One of the most important scientific facilities nowadays is The European Organization for Nuclear Research known as CERN. It is located near Geneva, Switzerland and it is the largest particle physics laboratory in the world. The main function of this facility is to provide particle accelerators and other infrastructures for high-energy physics experiments. The biggest of its accelerators is LHC – Large Hadron Collider. CERN is also the birthplace of World Wide Web!
Picture 56: CERN logo (CERN, 2016)
An atom is made up of smaller particles: There is a central nucleus made up of protons and neutrons. Around this, electrons orbit at high speed. The numbers of particles depends on the type of atom. Protons have a positive (+) charge. Electrons have an equal negative (-) charge. Normally, an atom has the same number of electrons as protons, so its total charge is zero. Protons and neutrons are called nucleons. Each is about 1800 times more massive than an electron, so virtually all of an atom’s mass is in its nucleus. Electrons are held in orbit by the force of attraction between opposite charges. Protons and neutrons are bound tightly together in the nucleus by a different kind of force, called strong nuclear force. Elements and Atomic Number All materials are made from about 100 basic substances called elements. An atom is the smallest ‘piece’ of an element you can have. Each element has a different number of protons 90
in its atoms: it has a different atomic number (sometimes called the proton number). The atomic number also tells you the number of electrons in the atom. (Pople, 2010, p. 250) a. b. c. d.
What does every atom consist of? What is the mass of an electron in comparison with the mass of a proton? Which particles are bound together by the strong nuclear force? What is the atomic number?
a.
b.
c.
d.
2. There is a picture of an atom of He with its approximate size. Look at it and answer the following questions.
Picture 58: Helium atom (Yzmo, 2011)
a. What example would you present to your students to help them visualize the dimensions of an atom and its nucleus? b. What is an angstrom (ångström)?
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a.
b.
3. Use the periodic table of elements in the picture and answer the following questions.
Picture 59: Periodic table of elements (Science Notes, 2016)
a. b. c. d.
What is the atomic number of phosphorus? What is the atomic mass of sodium? What is the element symbol of arsenic? What is the element name of Al?
a. b. c. d.
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4. Nuclei of some atoms are unstable and they break up while emitting a radiation. Fill in the gaps in the article about radioactivity with the expressions in the box. break up decay element
emit powerful radioactive
radioactivity rays
Radioactivity The nuclei of atoms of ___________ elements are unstable. This means they _____ __ naturally, releasing nuclear radiation (usually just called radiation). This process is called ____________. Radiation consists of alpha, beta, and gamma _____. Alpha rays are the weakest, and gamma rays are the most ________, although all three types of radiation can be dangerous. When the nucleus of an atom _____ alpha or beta rays, it changes, and the atom becomes an atom of a different element. This change is called _____. A radioactive series is a series of elements formed by the successive decay of one _______ into another. (Tulajová, 2000, p. 33)
X-radiation (X-rays) is a form of electromagnetic radiation with the wavelength between 0.01 an 10 nanometres. X-rays are widely used in medical radiography, airport security or crystallography. X-radiation is often referred to as Röntgen radiation, after the German physicist Wilhelm Röntgen who discovered this kind of rays. In spite of many advantages, X-rays are classified as carcinogen and excessive exposure to this radiation is dangerous!
Picture 60: Hand with Rings - one of the first X-rays (Röntgen, 1895)
5. The article above mentions three types of radiation. Match the types of radiation with their properties. what it consists of
ionizing effect penetrating effect
alpha particles
2 protons + 2 electron neutrons (like a nucleus of helium-4) very weak weak never completely stopped; lead and thick concrete reduce intensity
beta particles
electromagnetic waves (photon) strong
stopped by a thick stopped by sheet of paper, by millimetres skin, or a few aluminium centimetres of air
a
few of
gamma rays
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6. The exercises above mention ionizing effects. Explain in a few sentences what it means. The picture and the expressions in the box might help you. conduct an electric current damage or destroys cells dangerous charged atom
ion ionized ionizing radiation lose/gain electron
remove electron ultraviolet radiation X-rays
Picture 61: Ionization scheme (Costa, 2015)
7. Half-life is the time needed for exactly the half of the nuclei in the radioactive sample to decay. Iodine-131 has a half-life of 8 days. If there are 20 million nuclei of iodine-131, how much time does it take to have a sample with only 2.5 million of undecayed nuclei?
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a. Create a similar task for your students to test the knowledge of half-life. b. A related quantity is defined as the number of decays per unit of time (second). Its unit is becquerel (Bq). What is the name of the quantity? a.
b.
8. Read the article and answer the following questions. grandstand plaque self-sustaining conceive dare destructiveness disappear flash frightening charge initiate
tribuna plaketa soběstačný vymyslet, představit si odvážit se ničivost zmizet záblesk děsivý nálož, náboj zahájit, spustit
perish posterity prodigious
zahynout potomstvo velkolepý
record recover release stark target thereby vapour perish
zaznamenat vzpamatovat se uvolnit tvrdý, drsný cíl tímto, čímž pára zahynout
The Atomic Age On the west end of Stagg Field at the University of Chicago, where the grandstands were located, a bronze plaque reads as follows: ON DECEMBER 2, 1942 MAN ACHIEVED HERE THE FIRST SELF-SUSTAINING CHAIN REACTION AND THEREBY INITIATED THE CONTROLLED RELEASE OF NUCLEAR ENERGY. In these simple but dramatic words, Enrico Fermi (1901 – 1954) and his co-workers recorded for posterity the historic event of the first successful experiment in unlocking the prodigious sources of energy stored within the nucleus of the atom. Two and a half year later, at dawn of July 16, 1945, the first atomic bomb was exploded on the sands of New Mexico, and three weeks after this, on August 6, 1945, the world was to be electrified – and horrified – by the explosion of the first atomic bomb over a populated military target. Hiroshima, a city in Japan of 300, 000 people, lay in ruins from the explosion of a single bomb containing a charge of no more than a few pounds. In a single flash – hotter than the centre of the Sun – 70, 000 inhabitants perished outright, and a whole section of the city disappeared in vapour. The immediate result of the explosion of this bomb, and of another bomb over Nagasaki two days later, was the quick ending of World War II. But the unparalleled destructiveness of the bomb left humanity with a frightening problem. A giant had been released – one far more terrible and far more powerful than any mythological monster conceived by the imaginative 95
Greeks. No story teller throughout history had dared invent such a monster. Yet he was here – a stark reality. Would this giant be a menace threatening to destroy civilization and all human life on this planet, or would it be possible to tame him and use his enormous strength to do the work of the world? How could the giant be controlled? These were the questions that thoughtful men everywhere asked, after they recovered from the shock. (Herzlík, 1987, p. 55) a. b. c. d.
What happened on December 2, 1942? Why was the world horrified on August 6, 1945? What is meant by the “frightening problem “ in the third paragraph? Nuclear energy is one of a few cross-cultural topics in teaching physics. Based on the article, create two test questions for your students that would connect both physics and history.
a.
b.
c.
d.
9. The author of the article mentions a nuclear chain reaction. The picture below shows such a reaction called fission. Form the description of this phenomenon by putting the sentences in order.
Picture 62:Chain reaction (Nuclear Science in Society, 2016)
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This is called fission. The nucleus becomes highly unstable and splits into two lighter nuclei. The chain reaction develops when the released neutrons go on splitting other nuclei and a huge amount of energy is released. A neutron strikes a nucleus of uranium-235. At the same time it shoots out two or three neutrons and releases energy.
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12. Astrophysics 1. Read the article and answer the following questions. accompany bound to compelling discernible fate illumination immediately likewise mediocre
doprovázet svázán s přesvědčivý, pádný rozeznatelný osud osvětlení okamžitě, bezprostředně podobně, stejně tak průměrný
mere noble nourishment preliminary resource sensible stepping stone
pouhý vznešený výživa, živiny předběžný, úvodní zdroj vnímatelný odrazový můstek
surface yardstick
povrch pravítko
The Sun, the Nearest Star Although the Sun is one of millions of stars and a rather mediocre one at that, we shall begin to study the stars with it for several reasons. The Sun is our star. It is the resource of illumination and nourishment, and it is necessary for the very existence of all life on the Earth. Plato in his Republic called the Sun “the most noble and most perfect of all bodies” in the sensible world. Together with the other planets the Earth is bound to the Sun by gravity and accompanies the Sun in all its journeys among the other stars. Its fate is inseparably connected to that of the Sun. More immediately compelling than any of the reasons, however, is the fact that the Sun is the nearest star. All other stars, however big or bright, appear as mere points of light even in the largest telescopes. No surface features are discernible, and no hope appears that they will ever be. On the other hand, we can observe the surface of the Sun directly, and study its structure. We can measure the Sun’s temperature, and its brightness, its mass, and its size. Its distance from the Earth is the basic yardstick by which all other astronomical distances are measured. Its mass, its size, and its brightness likewise serve as the units of comparison of stellar objects. The methods by which the solar quantities are determined are the same methods that are later applied to the study of the stars. In fact the Sun is the preliminary stepping stone to the world of stars. (Herzlík, 1987, p. 31) a. Why is the Sun so special to us though it is just a mediocre star? b. The distance between Earth and Sun is 1.496·1022 m. What is this distance used for? What is the name of this unit? c. What do we use its mass, size and brightness for? a.
b.
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c.
2. There are some specific values in the table below. Match these values with the physical properties of the Sun. 1.988·1030
1.392·109
5,700
1.57·107
diameter (m) mass (kg) temperature at surface (°C) temperature at centre (°C)
3. The Solar System consists of 8 planets. In the picture below there are all 8 planets and Pluto which is no longer considered a planet. State names of all 8 planets.
Picture 63: Solar System (Pics About Space, 2016)
a.
b.
c.
d.
e.
f.
g.
h.
There are 9 planets in the picture on the left though The Solar System consists of only 8 planets. The 9th one is the dwarf planet Pluto which used to be considered a planet until 2006. More massive objects had been discovered in The Solar System so the term “planet” was redefined which led to the exclusion of Pluto and establishing the new category “dwarf planet”.
4. The Earth makes two kinds of motion in relation with the Sun. It spins on its axis and it also orbits the Sun. Read the following statement and say whether it is right or wrong. Day and night take turns because the Earth orbits the Sun. How long does it take for the Earth to spin once? How long does it take for the Earth to move around the Sun once?
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5. The only natural satellite of the Earth is the Moon. Its movement causes the phenomenon that is called phases of the Moon. The pictures below show 4 different phases of the Moon. Match them with their names. full moon
new moon
waxing
waning
Picture 64: Phases of the Moon
6. Explain the term eclipse. You can use the words in the box. What kind of the eclipse is in the picture? Solar or lunar eclipse? block Earth eclipse
line up Moon partial
penumbra shadow source of light
Sun total umbra
Picture 65: Eclipse diagram (Crystalinks, 2016)
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7. Read the article and answer the following questions. belief develop invent
víra, přesvědčení vyvinout, rozvinout vymyslet, vynaleznout
promote religious
podporovat, prosazovat náboženský
Copernicus Nicholas Copernicus was born in 1473 in Poland, so he lived before telescopes were invented. He is famous for developing the heliocentric model of the Solar System, but he did not invent the idea himself. ‘Helio’ means ‘Sun’ in the Greek language. He used ideas from other astronomers, such as the Greek astronomer Aristarchus who had produced a model with the Sun at the centre about 1200 years earlier. Islamic astronomers, such as Al-Biruni, had also suggested heliocentric models. Copernicus promoted the heliocentric model in Europe. In the heliocentric model the Sun is at the centre of the Solar System and all the planets are in orbits around the Sun. This model was able to explain the motion of the planets much more simply. In this model the Moon was in orbit around the Earth. The fact that the heliocentric model was much simpler than the geocentric model is very important. Scientists always look for the simplest explanations of their observations. If explanations begin to get very complicated, then they will look for a simpler explanation. It was very difficult for Copernicus to openly discuss his heliocentric model. Everyone believed the Earth to be at centre of the Universe at the time. This was an important part of religious beliefs. Copernicus was worried that he would be persecuted if he published his ideas. His book about the heliocentric model was published as he died. It was published in Latin, which was not a language that many people could understand. (Reynolds, 2013, p. 66) a. People in the past believed in the geocentric model of the Solar System. Only later was the heliocentric model promoted by Copernicus. What is the difference between these two models? b. Why was it difficult for Copernicus to present his findings? a.
b.
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8. Complete the table with at least one piece of information about these famous people.
G. Galilei
V. Remek
The International Space Station (ISS) is the most complex international scientific and engineering project in history and the largest structure humans have ever put into space. This high-flying satellite is a laboratory for new technologies and an observation platform for astronomical, environmental and geological research. As a permanently occupied outpost in outer space, it serves as a steppingstone for further space exploration.
N. A. Armstrong
Y. A. Gagarin
J. Kepler
Picture 66: International Space Station (NASA, 2015)
9. Based on the work of Tycho Brahe, Johannes Kepler proposed 3 laws that described the motion of the planets in the Solar System. This happened in early 1600s. There are 3 statements that Kepler made. Match them with the names of the laws. The Law of Equal Areas
The Law of Harmonies
The Law of Ellipses
The path of the planets about the sun is elliptical in shape, with the centre of the Sun being located at one focus.
An imaginary line drawn from the centre of the sun to the centre of the planet will sweep out equal areas in equal intervals of time.
The ratio of the squares of the periods of any two planets is equal to the ratio of the cubes of their average distances from the sun.
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13. Key 1. Measurement 1. a. A platinum-iridium bar. b. A meter is one-ten-millionth of Earth’s meridian quadrant at sea level. c. There exists abundance of physical units and the SI system was introduced to unify these. d. No, the only basic unit of length in the metre. Inch, foot, nautical mile, parsec, astronomical unit, yard, light year, ... 2. Measuring Instrument tape, ruler, micrometer, vernier calipers
Unit
Unit Symbol
Physical Quantity
metre
m
length
kilogram
kg
mass
balance
second
s
time
stopclock, stopwatch
ampere
A
electric current
ammeter
kelvin
K
thermodynamic temperature
thermometer
mole
mol
amount of substance
---
candela
cd
luminous intensity
---
3. For example: newton – N – force, joule – J – work, pascal – Pa – pressure, volt – V – potential difference, hertz – Hz - frequency 4. unit
value
unit
value
inch (in)
25.4 mm
UK gallon (gal)
4.564 l
foot (ft)
304.8 mm
US gallon (gal)
3.785 l
yard (yd)
914.4 mm
US barrel (barrel)
159 l
statute mile (mi)
1,609.3 m
knot (kn/kt)
1.852 km/h
US fluid ounce (fl oz)
29.573 ml
mach (Ma/M)
1193.256 km/h
UK pint (pt)
568.261 ml
pound (lb)
0.454 kg
5. a. 1013.25 hPa, 101.325 kPa b. 150 ml c. 6378.1 km 103
d. 390 – 700 nm e. 20 kHz f. up to 3 GHz 6. To measure the thickness of one sheet of paper with a ruler we take a stack of papers, for example 50 sheets (we have to know the exact number of sheets) and we measure the thickness of the whole stack. Once we have measured the thickness, we divide the value by the number of sheets and then we get the result. 7. Take more sheets of paper (for example 50) so it is possible to measure the thickness of the stack of the papers. Measure and then divide the number by 50. The result will more accurate than if you tried to measure thickness of one separate sheet. 8. a b
3 4
c d
1 2
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2. Kinematics 1. a. Speed tells us just how fast the object moves. Velocity has two components – the speed of the object and the direction of travel. b. The car is almost always either a accelerating or decelerating so the instantaneous speed changes very often. Thus it is different from the average speed. c. Every vector has the magnitude and direction. d. The steady motion is uniform; the accelerated/decelerated motion is non-uniform. 2.
Human walk: 5 km/h or 1.39 m/s; motorway limit: 130 km/h or 36,1 m/s; speed of sound: 1224 km/h or 340 m/s; speed of light: 299,792,458 m/s.
3.
speed
velocity
acceleration
The rate at which an object moves. It is the measurement of the distance travelled by an object in a certain unit of time. (5) The speed and direction of an object. The velocity of a moving object changes if either its speed or its direction changes. For example, if a car travels around a corner at a constant speed, its velocity changes because the car is changing direction. (5) The rate of change of velocity. When the velocity of an object increases, it is accelerating. Acceleration is a change in velocity over a certain amount of time. When velocity decreases, the rate of change is called deceleration. (5)
4. motion
description
example
non-uniform motion
covers unequal distances in breaking or accelerating car equal interval of time
oscillatory motion
is repetitive and fluctuates string on a guitar between two locations
rotational motion
occurs when an object spins
train wheel
translational motion
results in a change of location
bullet fired from a gun
uniform motion
covers equal distance equal interval of time
in car with the cruise control on (steady speed)
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5. C: The car is decelerating. Its instantaneous speed decreases every second. The motion is decelerated, thus non-uniform. D: At the beginning the car is travelling at a steady speed of 20 m/s. Then it stops and does not move anymore. 6. A very important example of uniformly accelerated motion is the vertical motion of an object in a uniform gravitational field. If we ignore the effects of air resistance, this is known as being in free-fall. In the absence of air resistance, all falling objects have the same acceleration of free-fall, independent of their mass. 7. a. No. The mathematical model of Brownian motion relates to various quantities. b. According to Brownian motion, the particles from the region of higher concentration will be moving to the other region and the number of particles in both regions will become even in some time. c. Diffusion. Tea infusion, pollen particles in water. 8. The length of the track between Tokyo and Osaka is roughly 564 km.
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3. Dynamics 1. a. The force can change the shape and/or shape of the object. It also can change the direction of its motion. b. Force is a vector – it has both the magnitude and direction. If we want to be correct, we should put arrow above the symbol of the quantity - 𝐹⃗ . c. The article mentions gravitational force, electrostatic force, magnetic force, friction, water and air resistance. Other forces that can be mentioned: tension force, spring force, applied force (push or pull). d. Objects that are charged (positively or negatively). If the two objects are both positively (or negatively) charged, they repel each other. If they have opposite charges, then they attract each other. e. The liquid exerts the buoyancy force upon the bottle. The bottle does not sink as a result of its low density in comparison with the liquid. 2. When a force is applied to the force meter (we can for example pull the hook with the hand as shown in the picture or e can suspend a weight), the spring stretches and we can read the value of the force on the scale. When you release the hook, the spring returns to its initial position. The force meters used for demonstrating purposes usually measure the force in newtons (N). 3. Newton’s First Law If no force acts on a body, the body’s velocity cannot change; that is, the body cannot accelerate. Newton’s Second Law The net force on a body is equal to the product of the body’s mass and it acceleration. Newton’s Third Law When two bodies interact, the forces on the bodies from each other are always equal in magnitude and opposite in direction. (9) 4. scalars
vectors
area
acceleration
density
displacement
distance
force
energy
momentum
mass
velocity
speed potential difference
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5. Draw in the diagonal from O and measure its length. The diagonal represents the 3 resultant in both magnitude and direction. (Below, for example, the resultant is a force of 60 N at 26° to the horizontal.) On paper, draw two lines from O to represent the vectors. The directions must be 1 accurate, and the length of each line must be in proportion to the magnitude of each vector. 2 Draw in two more lines to complete a parallelogram.
6. a. Yes, there is. It is called sliding friction and it occurs when one object slides on another. The example might be the friction between a sledge and snow. The sliding friction is the reason why we can write with a pencil. b. Pulling blocks made of different material on a desk and measuring the force that makes the block move. c. We can make the surfaces smother, use some kind of liquid smoother layer on the surfaces, reduce the normal force, ... d. When a ball or a cylinder rolls along the surface of another body it slightly presses into the surface thus the rolling body constantly “climbs a hill”. The harder the surfaces are, the smaller the rolling friction is. Rolling friction also depends on the forces of adhesion that act between the surfaces.
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4. Rigid Body 1. a. A rigid body is an idealized model of an object that has a definite and unchanging shape and size. No body is the rigid body in the real world. b. It is the point in a body where the gravitational force has its origin. c. No. No real-world object is in fact a rigid body. For the purposes of simplification we think of the wooden plank as if it was the rigid body. 2. a. First, suspend the object (a card in this case) from some point so it hangs vertically. b. Suspend the plumb from the same point and record the plumb line. The centre of mass lies somewhere along this line. c. Rotate the object and suspend it at a different point. d. Again suspend the plumb from the same point and record the plumb line. e. The point where the two plumb lines intersect is the centre of mass. 3. a. The stool stands stably on the ground. The force acting on the stool has no turning effects. b. The stool is slightly tilted so the force turns it back to its original position. c. With a large tilt the centre of mass passes over the edge of the base and the turning effect of the force makes the stool tip over. 4.
Picture 67: Equlibria
5. moment of a force about a point = force × perpendicular distance from the point a. The seesaw is in equilibrium. The forces are different but also the distances from the fulcrum are different but the moments of those forces are balanced. b. The person in closing the door no. 1 would have to act with bigger force but in both cases, the momentum as the same value. 6. inclined plane lever pulley
a slope that reduces the effort needed to move something a bar that turns on a pivot in order to exert a force a grooved wheel, or set of wheels, around which a rope passes in order to move a load a grooved wheel, or set of wheels, around which a rope passes in order to move a
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screw
a shaft with a spiral groove
wheel and load a rotating devices that exerts a force at its centre when the outer axle part is turned, and vice versa 7. First-class lever: The load and effort (force) are located on the opposite sides of the fulcrum. For example seesaw or scissors. Second-class lever: The load is located between the fulcrum and the effort (force). For example wheelbarrow or bottle opener. 8. a. The mechanical work depends on the force exerted and the distance moved. b. The article explains energy as a quantity that characterizes the object’s ability to do work. c. When the object is hot the particles move faster thus and have higher kinetic energy thus overall energy of the object is higher. 9. m - mass g – gravitational acceleration h – height v - velocity 10. The bob has the biggest potential energy at the position 1 because it is at the highest point. The kinetic energy is the biggest at the position 3 because it has the biggest velocity. 11. Physical Quantity
Quantity Symbol
Unit
Unit Symbol
force
F
newton
N
moment
M
newton metre
N·m
energy
E
joule
J
work
W
joule
J
pressure
p
pascal
Pa
12. a. The first of them is a fixed pulley and the second one is a movable pulley. b. Fixed pulley: 50 N, movable pulley: 25 N. c. No, the amount of work needed to lift the load to a certain height is the same in both cases. d. A tackle and block is system of two or more fixed and movable pulleys with a rope used to lift heavy loads. 13. Ek=7848 J
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5. Liquids and Gases 1. a. Pascal’s principle. b. The pressure exerted on the object by the liquid is dependent on the density of the liquid and the depth of submersion. c. Hydrostatic pressure. d. If we calculate only the part of the pressure exerted by water, the result is 500 kPa. To calculate the total pressure on the diver, we must involve the atmospheric pressure and the answer is 501.3 kPa. 2. hydrostatics Bernoulli's equation buoyancy capillary action hydraulic lever hydrostatic pressure Pascal’s principle surface tension viscosity
hydrodynamics
laminar flow turbulent flow vortex waves
3. The term fluid incorporates both liquids and gases so water is both the liquid and fluid. substance
liquid
fluid
water
X
X
oxygen petrol
X X
X
sand methane
X
4. The pressure inside the liquid depends on the density of the liquid and the depth in which we measure the pressure. It does not depend on the shape of the container so the pressures p1 – p5 will be the same. 5. The pressure at the bottom of the dam is 580 KPa. Dams have to withstand the bigger pressure the lower the depth is, so dams are usually the thickest at the bottom. 6. Submerged, upwards, displaced.
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7. a. B stands for buoyancy of buoyant force and G is gravity or gravitational force. b. In the first case the buoyant force is greater so the cube tends to do upwards. This happens because the material of the cube has lesser density than water. In the third case the cube has higher density than water so the gravitational force is bigger and the cube tends to sink. c. The buoyant force is dependent on the volume of the cubes so it does not change if the volume stays the same. The gravitational force is dependent on the mass of the cubes which means that if the density changes, then the mass changes and consequently also the gravitational force changes. d. A: wood, plastic; C: iron, lead. 8. To conduct this experiment we need the Magdeburg hemispheres and a vacuum pump. The two hemispheres are attached as shown in the picture and the air from inside of the sphere is removed. Since there is almost a vacuum inside the sphere, the pressure outside the spheres is far greater. Atmospheric pressure acts equally on both hemispheres and holds them together. It is very difficult to pull them apart. 9. a. Hydraulic jack is a device used to lift up cars or other heavy objects. Also known as hydraulic lever. b. Incompressibility – liquids are almost incompressible so they can pass on any pressure applied to them. c. The two pistons have different diameter. If the first piston acts with a force and induces the pressure in the liquid. According to Pascal’s law, the same pressure acts on the second piston and induces the force that is different from the previous one (the second force is bigger if the diameter of the second piston is bigger). 10. Performed, tube, observed, descent, column, experiment, results. 11. h=10.1 m
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6. Thermodynamics 1. a. Liquid thermometers are based on the thermal expansion of the liquid inside – when the temperature rises, the volume of the liquid increases, the level rises and we can read the temperature. Liquid thermometers mostly make use of mercury and alcohol. b. In degrees Celsius - °C, degrees Fahrenheit - °F or kelvins – K. c. The thermal energy will double but the temperature will stay the same. d. The energy that is needed to heat up the object depends on mass of the object, its material and the temperature change. 2. solid/solid state liquid/liquid state gas/gaseous state The particles are in fixed The particles can move The particles can move positions; they vibrate. about – change positions freely and they vibrate. and they vibrate. 3.
Picture 68: States of matter
4. Cools, liquid, temperature, increased, sublime, dry ice, solid. 5. a. To increase evaporation you can increase the temperature, increase the surface area, reduce humidity or blow air across the surface. b. The atmospheric pressure at the top of Mt. Everest is lower so the vapour bubbles do not have to overcome such a pressure as at the sea level and the water starts boiling at only 70 °C. c. When the liquid evaporates the faster particles escape and the slower ones (the cooler ones) are left behind. The sweat evaporates from the surface of the body and takes away the thermal energy from the skin.
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6.
The radiation from the Sun passes easily through the atmosphere and heats up the surface of the Earth. The ground then heats up the air and the hot air is trapped in the atmosphere. Some layers of the atmosphere reflect the heat back and prevent the hot air from escaping and flowing away.
7. contraction expansion heat heat radiation thermal conduction thermal convection thermal insulator
a shrinking in size when something gets colder an increase in size when something gets hotter the kind of energy that makes things hot or cold the flow of heat in the form of infrared rays, which do not need a material or medium to transfer heat the flow of heat through a solid the flow of heat through a fluid a material that resists the flow of heat
8.
Picture 69: Internal structure of a vacuum flask with description (Physics World, 2006)
a. The silver coating reflects back the heat radiation from the hot liquid and thus helps to keep it warm. b. Good heat conductors are for example metals. Water is not considered to be a good heat conductor but it is for example far better heat conductor than air. 9. intake
compression
expansion
exhaust
10. Fahrenheit, Kelvin 11. a. The first paragraph – Fahrenheit The second paragraph – Kelvin 114
b.
Picture 70: Temperature scales (Pearson Prentice Hall, Inc., 2010)
12. Q=1.575 MJ
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7. Electricity 1. a. b. c. d.
Electrostatic charge or static electricity. A plastic rod becomes charged when rubbed with a woollen cloth. The closer the charges, the greater the force between them. An atom consists of protons and neutrons in the nucleus and electron orbiting the nucleus.
2. Electric charge can be detected using a leaf electroscope as above. If a charged object is placed near the metal plate, charges are induced in the electroscope. Those in the metal plate and metal stem repel so the leaf rises. 3. Physical Quantity
Quantity Symbol
Unit
Unit Symbol
Measuring Instrument
electric charge
Q
coulomb
C
electroscope
electric current
I
ampere
A
ammeter
potential difference, voltage
U, V
volt
V
voltmeter
resistance
R
ohm
Ω
ohmmeter
power
P
watt
W
wattmeter
energy
E
joule, kilowattJ, kWh hour
4. electric field electric current electrostatic induction direct current (DC) alternating current (AC) electrical conductor resistance
----
the area around a charged object in which it exerts a force the flow of electric charge through a substance the way in which a charged object produces an electric charge in another object electric current in which flows in one direction only electric current in which electrons change direction many times per second a substance through which electricity can flow the degree to which a substance resists electric current
5. Conductor, metals, conduction, insulator, plastic, safe, coverings. 6. conductors: copper, iron, salty water, aluminium, mercury insulators: plastic, wool, rubber, glass, cotton 7.
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a. There are lamps, ammeters, switches and power supplies. Others might be voltmeters, diodes, resistors... b. The first circuit – the bulbs are in a parallel connection; the other one is a series connection. c. If one of the bulbs is removed from the first circuit, the electric current would only flow through the second branch and the second bulb keeps working. If one of the bulbs in the second circuit is removed, the other will also go out because the circuit is interrupted. d. In series connection, the bulbs have each half of the voltage from the power source. In the parallel connection both bulbs have the same voltage from the source so they glow brighter. 8. Ohm’s law states that the current flowing through a piece of metal is proportional to the potential across it while the temperature remains constant. 9. a. Power is the rate at which is the electrical energy transferred or converted. b. 1 kWh=3,600,000 J. 10. a. LED lamps are the most efficient ones. They need the least energy (from the three types) to transfer it and give out certain amount of light. b. You would 624 crowns per year for the incandescent bulb and 104 crowns for the LED bulb. c. CFL – Compact Fluorescent Light
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8. Magnetism 1. a. Permanent magnets, magnetized objects and conductors with electric current. b. The magnet placed in the magnetic field of another magnet is attracted or repelled based on the position of their poles. c. The magnet will line up with the magnetic field of the Earth. The north pole of the magnet will point to the North Pole of the Earth. d. Domains are tiny magnetic regions in a magnetic material such as iron. 2. Magnetic field Magnetic pole
the area around the magnet in which it exerts force one of the two points in a magnet where its magnetism is the strongest
Domain
a small magnetic area in a magnetic material
Magnetic induction
the production of magnetism in another object by a magnet
Electromagnet
a form of a magnet that works by electricity
Magnetic field lines
lines that help us to visualize a magnetic field
3. Magnetic field lines spread out from one pole, curve around the magnet, and return to the other pole. The magnetic field is strongest at the poles. 4.
Picture 71: The Earth's magnetic field with description (Brashford, 1990)
5. Coil, wire, current, magnetizes, the core, temporary, steel, permanently, turns, direction.
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6. If you hold the thumb, index finger and middle finger of your left hand at the right angles in the way that index finger point in the direction of the magnetic field and the middle finger points at the direction of the current, then the thumb shows the induced force. 7.
Picture 72: Simple DC motor with description (Hasselo, 2016)
increasing the current using a stronger magnet increasing the number of turns on the coil increasing the area off the coil. (A longer coil means higher forces because there is a greater length of wire in the magnetic field; a wider coil gives the forces more leverage.)
8. 4 6 3 5 1 2
This breaks the circuit, the contacts no longer touch each other, and the core is no longer magnetised. The sequence starts again so the bell keeps ringing for as long as the bell-switch is pressed. The striker is attracted to the core and hits the bell producing a sound. The striker springs back and completes the circuit again. Someone presses the bell switch thus the circle is complete. A current passes through the coil and the iron core is magnetised.
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9. Waves and Sound 1. a. A thing has to vibrate to produce sound. For example: drumskin, tuning fork, loudspeaker, guitar string b. No, sound needs a medium to travel through. c. Vibrating things make the articles of surrounding medium vibrate. Those particles pass on the disturbance to the other layers of the medium so the wave propagates. Once it arrives to a human ear, it makes the eardrum vibrate and the brain perceives it as sound. d. Metal or plastic Slinky spring. e. The speed of the sound depends, besides other factors, on the medium which the sound travels through. 2. Period
The time taken for one complete oscillation, i.e. the time taken for one complete wave to pass any given point.
Frequency
The number of waves passing any point per second.
Wavelength
The distance between any point on a wave and the corresponding point on the next.
Amplitude
The maximum displacement from the mean position.
3. Radiation, loses, nucleus, space, angles, strikes, carries. 4. Sound needs a medium to travel through, for example air, metal or water. When the air is removed and there is almost vacuum surrounding the bell, there are no particles that could vibrate and so the sound wave cannot travel. Thus the bell seems quiet even though it is ringing. 5. Rustling leaves – 10 dB, conversational speech – 60 dB, busy road – 80 dB, disco – 100 dB, threshold of pain – 130 dB. 6. a. Longitudinal waves are always mechanical because they result from the successive compressions and rarefactions of the medium. b. A sound wave is a longitudinal wave. c. The wavelength is the distance between two successive crests (for the transversal wave) or compressions (for the longitudinal wave). d. Amplitude.
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7. Wave
Example of energy transfer.
water ripples
A floating object gains an ‘up and down’ motion.
sound waves
The sound received at an ear makes eardrum vibrate.
light waves
The back of the eye (the retina) is stimulated when light is received.
earthquake waves
Building collapse during an earthquake.
waves along a stretched rope compression waves down a spring
A ‘sideways pulse’ will travel down a rope that is held taut between two people. A compression pulse will travel down a spring that is held taut between two people (6)
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10.Optics and Light 1. a. The luminous objects give out light. For example the Sun, a lamp, a candle. Light does not need any medium for its propagation. b. Opaque objects block out light. c. The opposite word is transparent. d. Umbra is a full shadow whereas penumbra is only a partial shadow. For example if the source of light is big enough, the edges of the shadow seem to be blurred – this is penumbra. 2.
Picture 73: Human eye with description (Sherafat, 2016)
3. Focusing, spectacles, distant, converge, thick, retina, they have still not met. Short sight is corrected by a concave (diverging) lens. Long sight is corrected by a convex (converging) lens. To ignite fire you have to use a convex lens so you had better be short-sighted! 4. a.
Picture 74: Ray diagram of a converging lens wit description
122
b. 1
The ray through the centre passes straight through the lens.
2
The ray parallel to the principal axis passes through the virtual focal point (focus) after leaving the lens. The ray through the real focal point (focus) leaves the lens parallel to the principal axis.
3
c. The image is real, inverted, larger than the object. d. The ray parallel to the principal axis leaves the lens as if it went from F. The ray through F’ leaves the lens parallel to the principal axis. The ray to the centre passes straight through the lens. The image is virtual, upright and smaller than object. 5. Eyepiece, magnified, object, real, image, magnification. 6. a. Red, orange, yellow, green, blue, violet. b. The highest frequency – violet (790 - 700 THz), the longest wavelength – red (740 – 625 nm) c. An object in a glass of water, prism, rainbow, drops of water. 7. How is the angle of incidence different from the angle of reflection? What are the two laws of reflection? 8. The image is the same size as the object. The image is as far behind the mirror as the object is in front. The image is laterally inverted. The image is virtual. 9.
Picture 75: Spoon with description (Applect Learning Systems Pvt. Ltd., 2015)
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11.Atomic Physics 1. a. An atom consists of protons and neutrons located in the nucleus and electrons in the outer shells. b. Protons are 1800 times more massive than electrons. c. Protons and neutrons. d. It is the number of protons in the nucleus. 2. a. An atom can be visualized as a pitch with a grain of rice in its centre. The pitch itself is the atom and the grain is its nucleus. b. The angstrom is a unit of length often used to express sizes of atoms and molecules. 1 Å = 10-10 m = 100,000 fm. 3. a. b. c. d.
15 22.990 As Aluminium
4. Radioactive, break up, naturally, radioactivity, rays, powerful, emits, decay, element. 5. alpha particles 2 protons + 2 neutrons (like a nucleus of helium-4) very weak stopped by a thick sheet of paper, by skin, or a few centimetres of air
beta particles gamma rays electron electromagnetic waves weak (photon) stopped by a few millimetres strong of aluminium never completely stopped; lead and thick concrete reduce intensity
6. Ionizing effects mean that certain types of radiation (for example X-rays or ultraviolet radiation) affect atoms in its path in the way that they lose electrons. Such atoms then become ionized. Ionization can be dangerous for living organisms because it damages or destroys cells. If a gas is ionized, it conducts an electric current. 7. It takes 24 days. b. Radioactive activity is the quantity that tells us the number of decays per unit of time. The unit is the becquerel (Bq). One Becquerel is one transformation per second. 8. a. Scientists accomplished the first self-sustaining chain reaction. 124
b. The world was horrified by the explosion of the first atomic bomb over the populated place. c. The “frightening problem” was the question whether the mankind would be able to control such a weapon and such a source of energy. 9. A neutron strikes a nucleus of uranium-235. The nucleus becomes highly unstable and splits into two lighter nuclei. At the same time it shoots out two or three neutrons and releases energy. This is called fission. The chain reaction develops when the released neutrons go on splitting other nuclei and a huge amount of energy is released.
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12.Astrophysics 1. a. The Sun is so special to us because it is the resource of illumination and nourishment, and it is necessary for the existence of all life on the Earth. b. This distance is used as a unit of length for measuring long distances in space. It is called Astronomical Unit (AU). c. The mass, size, and brightness serve as the units of comparison of other stellar objects. 2.
3.
diameter (m)
1.392·109
mass (kg)
1.988·1030
temperature at surface (°C)
5,700
temperature at centre (°C)
1.57·107
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus
4. The statement is wrong. Day and night take turns because the Earth spins on its axis. The Earth spins once in 24 hours. The Earth orbits the Sun once in 365 and ¼ days. 5.
new moon
waxing
full moon
waning
6. Eclipse means that the light from a stellar source is blocked by another planet or stellar object so the light does not reach the observer. There is a solar eclipse in the picture which means that the light from the Sun is blocked by the Moon and the observer on the Earth will see either the full eclipse or the partial eclipse according to his/her position on the Earth. 7. a. The geocentric model claimed that the centre of the Solar System is the Earth whereas in the heliocentric model the Sun is in the centre. b. The geocentric model was an important part of the religious beliefs at the time of Copernicus which means that he would have probably be persecuted for openly presenting such idea.
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8. G. Galilei V. Remek
An Italian astronomer, mathematician and philosopher famous for his work on falling objects and his support of the heliocentric model. The first and only Czech in space.
N. A. Armstrong
An American astronaut end the first person to walk on the Moon (1969).
Y. A. Gagarin
A Russian astronaut and pilot, the first man in space (1961).
J. Kepler
A German mathematician and astronomer, most famous for his laws of planetary motion.
9. a. The Law of Ellipses b. The Law of Equal Areas c. The Law of Harmonies
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14. Dictionary Measurement
Měření
ammeter
ampérmetr
amount of substance
látkové množství
ampere
ampér
analogue
analogový
arithmetic mean
aritmetický průměr
balance
rovnoramenné váhy
beaker
kádinka
body
těleso
candela
kandela
compare
srovnat, porovnat
cone
kužel
convert
převést
coordinates
souřadnice
cube
krychle
cubic meter
metr krychlový
cylinder
válec
decimal point
desetinná čárka
degree Celsius
stupeň Celsia
density
hustota
derived SI units
odvozené jednotky
digital
digitální, číslicový
dimension
rozměr
dimension symbol
značka veličiny
division
rozdělení, dílek na stupnici
128
electric current
elektrický proud
evaluation of data
zpracování hodnot
fundamental SI units, basic units
základní jednotky SI
height
výška
heterogeneous
nestejnorodý
homogenous
stejnorodý
instrumental error
chyba měřidla
International System of Units
Mezinárodní soustava jednotek
kelvin
kelvin
kilogram
kilogram
length
délka
luminous intensity
svítivost
mass
hmotnost
matter
látka
measure
měřit
measuring error
chyba měření
measuring instrument
měřidlo
mercury/liquid/bi-metal thermometer
rtuťový/kapalinový/bimetalový teploměr
meter
metr
micrometer
mikrometr
mole
mol
multiples of SI units
násobky jednotek SI
observation
pozorování
oscillation
kmitání
oscillatory motion
kmitavý pohyb
physical quantity
fyzikální veličina
pyramid
jehlan 129
scale
stupnice
SI system
soustava SI
sphere
koule
standard meter
prototyp metru
stopwatch
stopky
submultiples of SI units
díly jednotek SI
tape/self-retracting tape measure
krejčovský/svinovací metr
thermodynamic temperature
termodynamická teplota
time
čas
unit
jednotka
unit symbol
značka jednotky
value
hodnota
vernier calliper
posuvné měřidlo
volume
objem
width
šířka
Kinematics
Kinematika
accelerated motion
zrychlený pohyb
acceleration
zrychlení
average velocity
průměrná (rychlost)
circular/rotational motion
pohyb po kružnici
curvilinear motion
křivočarý pohyb
decelerated motion
zpomalený pohyb
displacement
posunutí
distance
vzdálenost
free fall
volný pád
instantaneous velocity
okamžitá (rychlost)
130
mass point
hmotný bod
motion
pohyb
non-uniform motion
nerovnoměrný pohyb
oscillatory motion
kmitavý pohyb
path
dráha
position/location
poloha
random motion
nepravidelný pohyb
rectilinear/straight-line motion
přímočarý pohyb
reference system
vztažná soustava
speed
rychlost
speedometer
tachometr
steady
stálý
trajectory
trajektorie
translatory motion
translační pohyb
uniform motion
rovnoměrný pohyb
velocity
rychlost
Dynamics
Dynamika
acceleration
zrychlení
attract
přitahovat
ball bearings
kuličkové ložisko
bearings
ložisko
centripetal force
dostředivá síla
couple of forces
dvojice sil
drag
táhnout, vléci
dynamic friction
dynamické tření
dynamics
dynamika
131
dynamometer/forcemeter
siloměr
effect of force
účinek síly
electric/electrostatic force
elektrická síla
force
síla
free fall
volný pád
friction
tření
friction force
třecí síla
gravitation
gravitace
gravitational field
gravitační pole
gravitational force
gravitační síla
gyroscope
setrvačník
inertia
setrvačnost
inertia
setrvačnost
inertial force
setrvačná síla
kinetic energy
kinetická (pohybová) energie
law of conservation of
zákon zachování
magnetic force
magnetická síla
mass
hmotnost
mass point
hmotný bod
moment of force, torque
moment síly
momentum
hybnost
net force
výsledná síla
Newton's law of gravitation
Newtonův gravitační zákon
Newton's laws of motion
Newtonovy pohybové zákony
noninertial reference frame
neinerciální vztažná soustava
origin of force
působiště síly
potential energy
potenciální (polohová) energie 132
power
výkon
projectile motion
vrh
repel
odpuzovat
represent
znázornit
resultant
výslednice
roller bearings
válečkové ložisko
rolling resistance
valivý odpor
sliding friction
smykové tření
static friction
klidové tření
superposition of forces
skládání sil
tension
napětí
thrust
vrazit, strčit, tah (motoru)
weight
tíha
work
práce
Rigid Bodies
Tuhá tělesa
angular momentum
moment hybnosti
anticlockwise
proti směru hodinových ručiček
axis of rotation
osa otáčení
axle
hřídel
bending
ohyb
block and tackle
kladkostroj
centre of gravity/mass
těžiště
clockwise
ve směru hodinových ručiček
compressive stress
tlakové napětí
couple of forces
dvojice sil
deformation
deformace
133
elastic deformation
pružná deformace
energy
energie
equilibrium
rovnováha
fixed pulley
pevná kladka
free/neutral equilibrium position
volná rovnovážná poloha
gyroscope
setrvačník
Hooke's law
Hookeův zákon
impact/collision of bodies
ráz těles
inclined plane
nakloněná rovina
inelastic impact
nepružný ráz
intersect
protínat se
joule
joule
kinetic energy
kinetická/pohybová energie
lever
páka
line of action of mass
těžnice
load
břemeno
moment of force
moment síly
moment of inertia
moment setrvačnosti
momentum
hybnost
movable pulley
volná kladka
newton metre
newton metr
pendulum
kyvadlo
perfectly elastic impact
dokonale pružný ráz
pivot
osa
plastic deformation
plastická deformace
plumb
olovo, olovnice
potential energy
potenciální/polohová energie 134
pressure
tlak
pressure deformation
deformace tlakem
pressure force
tlaková síla
pulley
kladka
rigid body mechanics
mechanika tuhého tělesa
screw
šroub
shear deformation
deformace smykem
shear stress
smykové napětí
stability
stabilita
stable equilibrium position
stálá rovnovážná poloha
stress
napětí
superposition of forces
skládání sil
tensile deformation
deformace tahem
tensile stress
tahové napětí
toothed wheel
ozubené kolo
torque
moment síly, krouticí moment
torsion
krut
unstable/labile equilibrium position
vratká rovnovážná poloha
weight
tíha
wheel
kolo
work
práce
Liquids and Gases
Kapaliny a plyny
altitude
nadmořská výška
aneroid
aneroid
Archimedes' principle
Archimedův zákon
at rest
v klidu
135
atmospheric pressure
atmosférický tlak
barograph
barograf
beaker
kádinka
buoyancy, upthrust
vztlak
buoyant force
vztlaková síla
capillary action
kapilární jevy
communicating vessels
spojené nádoby
compressible
stlačitelný
compressor
kompresor
depth
hloubka
float
plovat
flow
proudit
fluid
tekutina
gas
plyn
graduated/measuring cylinder
odměrný válec
homogenous
stejnorodý
hydraulic
hydraulický
hydraulic jack/lever
hydraulický zvedák
hydrometer
hustoměr
hydrostatic pressure
hydrostatický tlak
incompressible
nestlačitelný
inhomogeneous
nestejnorodý
internal friction
vnitřní tření
laminar flow
laminární proudění
level
úroveň, výška hladiny, vodorovný
liquid
kapalina
liquid
tekutý 136
manometer
manometr
medium resistance
odpor prostředí
overpressure
přetlak
Pascal's principle
Pascalův zákon
perfect/idealized fluid
dokonalá tekutina
pressure
tlak
pressure gauge
tlakoměr
real fluid
reálná tekutina
steady flow
ustálené (stacionární) proudění
surface
povrch, hladina
surface tension
povrchové napětí
syringe
injekční stříkačka
Torricelli's experiment
Torricelliho pokus
turbulent flow
turbulentní proudění
underpressure
podtlak
vacuum
vakuum
vacuum pump
vývěva
viscosity
viskozita
vortex
vír
water mark
vodoznak
Thermodynamics
Termodynamika
adiabatic process
adiabatický děj
anomaly of water
anomálie vody
boiling
var
Brownian motion
Brownův pohyb
calorimeter
kalorimetr
137
compression
stlačení
compression ignition/Diesel engine
vznětový spalovací/Dieselův motor
cooler
chladič
crystal lattice
krystalická mřížka
degree Celsius
stupeň Celsia
degree Fahrenheit
stupeň Fahrenheita
efficiency
účinnost
environment
okolí
evaporation
vypařování
exhaust
výfuk
expansion
roztažení
four-stroke/two-stroke
čtyřdobý/dvoudobý
gas
plyn
gaseous state
skupenství plynné
heat
teplo
heat capacity
tepelná kapacita
heat conduction
vedení tepla
heat conductor
tepelný vodič
heat convection
přenos tepla prouděním
heat engine
telený motor
heat radiation
sálání tepla
heat reservoir
ohřívač
humid
vlhký
intake
sání
internal combustion engine
spalovací motor
internal energy
vnitřní energie
isobar
izobara 138
isobaric process
izobarický děj
isochore
izochora
isochoric process
izochorický děj
isolated/unisolated systém
izolovaná/neizolovaná soustava
isotherm
izoterma
isothermal process
izotermický děj
jet-propulsion engine
proudový motor
kelvin
kelvin
latent heat
skupenské teplo
law/principle of thermodynamics
termodynamický zákon
liquefaction
zkapalnění
liquid
kapalina
liquid state
skupenství kapalné
melting/fusion
tání/tavení
open/closed systém
otevřená/uzavřená soustava
particle
částice
perpetual motion machine
perpetuum mobile
plasma
plazma
reaction engine
reaktivní motor
saturated vapour
nasycená pára
solid
pevná látka
solid state
skupenství pevné
solidification
tuhnutí
source of heat
zdroj tepla
spalovací komora
combustion chamber
spark-ignition engine
zážehový motor
specific heat capacity
měrná tepelná kapacita 139
state
stav
state of matter
skupenství látky
steam engine
parní stroj
sublimation/desublimation
sublimace/desublimace
temperatire of solidification/freezing point
teplota tuhnutí
temperature
teplota
temperature of boiling/boiling point
teplota varu
temperature of fusion/melting point
teplota tání
temperature scale
teplotní stupnice
thermal cycle
kruhový cyklus
thermal epansivity
teplotní rozpínavost
thermal insulant
tepelný izolant
thermal linear expansion
teplotní délková roztažnost
thermal volume expansion
teplotní objemová roztažnost
thermodynamic process
termodynamický děj
thermodynamics
termodynamika
thermometer
teploměr
transfer
přenos
transformation of state
změna skupenství
triple point
trojný bod
turbine
turbína
vacuum flask
termoska
vapour/steam
pára
wet
mokrý
adiabatic process
adiabatický děj
anomaly of water
anomálie vody
boiling
var 140
Brownian motion
Brownův pohyb
calorimeter
kalorimetr
compression
stlačení
compression ignition/Diesel engine
vznětový spalovací/Dieselův motor
cooler
chladič
crystal lattice
krystalická mřížka
degree Celsius
stupeň Celsia
degree Fahrenheit
stupeň Fahrenheita
efficiency
účinnost
environment
okolí
evaporation
vypařování
exhaust
výfuk
expansion
roztažení
four-stroke/two-stroke
čtyřdobý/dvoudobý
gas
plyn
gaseous state
skupenství plynné
heat
teplo
heat capacity
tepelná kapacita
heat conduction
vedení tepla
heat conductor
tepelný vodič
heat convection
přenos tepla prouděním
heat engine
telený motor
heat radiation
sálání tepla
heat reservoir
ohřívač
humid
vlhký
intake
sání
internal combustion engine
spalovací motor 141
internal energy
vnitřní energie
isobar
izobara
isobaric process
izobarický děj
isochore
izochora
isochoric process
izochorický děj
isolated/unisolated system
izolovaná/neizolovaná soustava
isotherm
izoterma
isothermal process
izotermický děj
jet-propulsion engine
proudový motor
kelvin
kelvin
latent heat
skupenské teplo
law/principle of thermodynamics
termodynamický zákon
liquefaction
zkapalnění
liquid
kapalina
liquid state
skupenství kapalné
melting/fusion
tání/tavení
open/closed system
otevřená/uzavřená soustava
particle
částice
perpetual motion machine
perpetuum mobile
plasma
plazma
reaction engine
reaktivní motor
saturated vapour
nasycená pára
solid
pevná látka
solid state
skupenství pevné
solidification
tuhnutí
source of heat
zdroj tepla
combustion chamber
spalovací komora 142
spark-ignition engine
zážehový motor
specific heat capacity
měrná tepelná kapacita
state
stav
state of matter
skupenství látky
steam engine
parní stroj
sublimation/desublimation
sublimace/desublimace
temperature of solidification/freezing point
teplota tuhnutí
temperature
teplota
temperature of boiling/boiling point
teplota varu
temperature of fusion/melting point
teplota tání
temperature scale
teplotní stupnice
thermal cycle
kruhový cyklus
thermal expansivity
teplotní rozpínavost
thermal insulant
tepelný izolant
thermal linear expansion
teplotní délková roztažnost
thermal volume expansion
teplotní objemová roztažnost
thermodynamic process
termodynamický děj
thermodynamics
termodynamika
thermometer
teploměr
transfer
přenos
transformation of state
změna skupenství
triple point
trojný bod
turbine
turbína
vacuum flask
termoska
vapour/steam
pára
wet
mokrý
143
Electricity
Elektřina
accumulator, cell battery
akumulátor
alternating current
střídavý proud
aluminium
hliník
ammeter
ampérmetr
ampere
ampér
appliance
spotřebič
attract
přitahovat
battery
baterie
bulb
žárovka
circuit
obvod
circuit breaker
jistič
conductor
vodič
connecting wire
vodič
connecting wire
připojit
consumer unit
rozvodná skříň
conventional current direction
dohodnutý směr proudu
copper
měď
coulomb
coulomb
cross-sectional area
průřez
diameter
průměr
diode
dioda
direct current
stejnosměrný proud
earth
uzemnit
electric cell
článek
electric current
elektrický proud
electric field
elektrické pole 144
electric field lines
siločáry elektrického pole
electric charge
elektrický náboj
electric power
elektrický výkon
electrical work
elektrická práce
electricity
elektřina
electrolytic solution
elektrolyt
electromotive voltage (force)
elektromotorické napětí
electron
elektron
electron flow
proud elektronů
electroscope
elektroskop
elementary charge
elementární náboj
energy
energie
filament
vlákno
flash
záblesk
free electron
volný elektron
fuse
pojistka
heating
zahřívání
imput power, power consumption
příkon
insulator
izolant
ion
ion
joule
joule
lead
olovo
light-dependent resistor, photoresistor
fotorezistor
lightning
blesk
like
souhlasné
mains
rozvodná síť
mains frequency
frekvence proudu v rozvodné síti 145
metal
kov
meter
měřicí přístroj
negative
záporný
neutron
neutron
nucleus
jádro
ohm
ohm
ohmmeter
ohmmetr
Ohm's law
Ohmův zákon
parallel connection
paralelní zapojení
pin (two-pin plug)
kolík
plug
zástrčka
polarization
polarizace
positive
kladný
potential difference
rozdíl potenciálů
power station
elektrárna
power supply
zdroj napětí
proton
proton
repel
odpuzovat
resistance
odpor
resistor
rezistor
semiconductor
polovodič
serial connection
sériové zapojení
silver
stříbro
socket
zásuvka
spark
jiskra
static electricity
statická elektřina
storm
bouře 146
switch
spínač
terminal
elektroda
thermistor
termistor
unlike, opposite
nesouhlasné
variable resistor
potenciometr
voltage
napětí
voltage
volt
voltmeter
voltmetr
watt
watt
wattmeter
wattmetr
wiring
elektrické rozvody
Magnetism
Magnetismus
align
seřadit se, orientovat se
alloy
slitina
artificial
umělý
attract
přitahovat
bar magnet
tyčový magnet
circuit breaker
jistič
cobalt
kobalt
compass
kompas
declination
deklinace
demagnetize
odmagnetovat
ferromagnetic materials
feromagnetické látky
flux
tok, proud
hard magnetic material
magneticky tvrdá látka
iron
železo
147
iron fillings
železné piliny
like
souhlasný
lodestone
magnetovec
magnet
magnet
magnetic
magnetický
magnetic domains
magnetické domény
magnetic field
magnetické pole
magnetic field lines
magnetické indukční čáry
magnetic field strenght (intensity)
intenzita magnetického pole
magnetism
magnetismus
magnetize
magnetovat
natural
přírodní
nickel
nikl
non-magnetic
nemagnetický
north-seeking pole, north pole
severní pól
permanent
trvalý
repel
odpuzovat
right-hand grip rule
ampérovo pravidlo pravé ruky
soft magnetic material
magneticky měkká látka
solenoid
cívka
south-seeking pole, south pole
jižní pól
temporary
dočasný
unlike, opposite
nesouhlasný
Waves and Sound
Vlny a zvuk
amplitude
amplituda
bend
ohnout
148
circular
kulový
compression
zhuštění
crest
vrch
diffraction
difrakce
displacement
výchylka
ear-drum
ušní bubínek
echo
ozvěna
frequency
frekvence
fundamental frequency
základní frekvence
glass
sklo
hertz
hertz
light
světlo
longitudinal
podélné
loudness
hlasitost
medium
prostředí
microphone
mikrofon
noise
hluk, šum
oscillation
kmit
oscilloscope
osciloskop
period
perioda
pitch
tón
propagate
šířit se
radiate
vyzařovat
rarefaction
zředění
ray
paprsek
reflection
odraz
refraction
lom (vlnění) 149
ripple
vlnka
slit
štěrbina
sound
zvuk
speaker
reproduktor
string
struna, vlákno
tank
nádrž, akvárium
timbre
barva (hlasu)
transverse
příčné
trough
důl
tuning fork
ladička
ultrasound, ultrasonic sound
ultrazvuk
vacuum pump
vývěva
vibration
vibrace
water
voda
wave
vlna
wave equation
vlnová rovnice
wavefront
čelo vlny
wavelength
vlnová délka
Optics and Light
Optika a světlo
aerial, antenna
anténa
angle of incidence
úhel dopadu
angle of reflection
úhel odrazu
angle or refraction
úhel lomu
attenutiaon
zeslabení
beam
paprsek, svazek paprsků
binoculars
dalekohled
150
coating
povrch
concave lens, diverging lens
rozptylná čočka
concave mirror
duté zrcadlo
contact lenses
kontaktní čočky
converge
sbíhat se
convex lens, converging lens
spojná čočka
convex mirror
vypuklé zrcadlo
cornea
rohovka
critical angle
kritický úhel
deviate
vychýlit
difuse
rozptýlený
dispersion
disperze
emit
vyzařovat
focal lenght
ohnisková vzdálenost
focal point, focus
ohnisko
focus
zaostřit
image
obraz
incident ray
dopadající paprsek
infrared
infračervený
intersect
protnout se
iris
duhovka
laterally inverted
stranově převrácený
lens
čočka
long sight
dalekozrakost
magnification
zvětšení
magnifying glass
lupa
medium
prostředí 151
object
předmět
optical fibre
optické vlákno
penumbra
polostín
periscope
periskop
photon
foton
plane mirror
ploché zrcadlo
prism
optický hranol
principal axis
hlavní osa
propagate
šířit se
protractor
úhloměr
pupil
zornice
ray
paprsek
ray
paprsek
real image
skutečný obraz
reflected ray
odražený paprsek
refractive index
index lomu
retina
sítnice
sclera
bělmo
screen
stínítko
shadow, umbra
stín
short sight
krátkozrakost
Snell's law
Snellův zákon
spectacles
brýle
spectrum
spektrum
total reflection
úplný odraz
transmit
přenášet, vysílat
ultraviolet
ultrafialový 152
virtual image
neskutečný obraz
vitreous body
sklivec
x-rays
rentgenové záření
Atomic Physics
Atomová fyzika
atom
atom
atomic mass
hmotnost atomu
background radiation
reliktní záření
becquerel (Bq)
becquerel (Bq)
cloud chamber
mlžná komora
concrete
beton
core
jádro
decay
rozklad
disintigration
rozpad
electron
elektron
element
prvek
emit
vyzařovat
emmission
vyzařování, emise
fission
štěpení
fusion
fůze
half-life
poločas rozpadu
chain reaction
řetězová reakce
ionization
ionizace
irradiation
ozáření
isotope
izotop
lead
olovo
neutron
neutron
153
nuclear
jaderný
nuclear reactor
jaderný reaktor
nuclear waste
jaderný odpad
nucleon
nukleon
nucleon (mass) number
nukelonové číslo
nucleus
jádro
nuclide
nuklid
particle
částice
path
dráha
penetrate
proniknout
periodic table
periodická tabulka prvků
photon
foton
plutonium
plutonium
proton
proton
proton (atomic) number
protonové číslo
radioactive
radioaktivní
ray
paprsek
sample
vzorek
shell (electron shell)
obal (elektronový obal)
shield
odstínit
stable/unstable
stabilní/nestabilní
turbine
turbína
unstable
nestabilní
uranium
uran
Astrophysics
Astrofyzika
astronaut, cosmonaut
kosmonaut
154
astronomer
astronom
astronomical unit, AU
astronomická jednotka, AU
astronomy
astronomie
atmosphere
atmosféra
axis
osa
Big Bang
Velký třesk
black hole
černá díra
comet
kometa
constellation
souhvězdí
coordinates
souřadnice
Earth
Země
eclipse
zatmění
equator
rovník
equinox
rovnodennost
first quarter
první čtvrť
full moon
úplněk
geocentric
geocentrický
geoid
geoid
gravity
gravitace
heliocentric
heliocentrický
infinite
nekonečný
inner
vnitřní
Jupiter
Jupiter
light year, l.y.
světelný rok, l.y.
line up
seřadit se
lunar
měsíční
Mars
Mars 155
Mercury
Merkur
meridian
poledník
meteor
meteor
meteorite
meteorit
Milky Way
Mléčná dráha
Neptune
Neptun
new moon
nov
orbit
obíhat, dráha
outer
vnější
parsec, pc
parsek, pc
penumbra
polostín
phases of Moon
fáze měsíce
planet
planeta
Pluto
Pluto
rotate
otáčet se
satellite
satelit
Saturn
Saturn
season
období
solar
sluneční
Solar System
Sluneční soustava
solstice
slunovrat
space
prostor, vesmír (mezihvězdný prostor)
space shuttle
raketoplán
spin
galaxie
spin
otáčet se
star
hvězda
stellar
hvězdný 156
Sun
Slunce
telescope
hvězdářský dalekohled
telescope
dalekohled
third quarter
poslední čtvrť
tilt
naklonit
tropic
obratník
tropic of Cancer
obratník Raka
tropic of Capricorn
obratník Kozoroha
umbra/shadow
stín
universe/cosmos
vesmír
Uranus
Uran
Venus
Venuše
waning
couvání (Měsíce)
waxing
dorůstání (Měsíce)
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6. Závěr V rámci diplomové práce Angličtiny pro učitele fyziky (English for Physics Teachers) jsme vytvořili kompletní učební text, který je určen pro studenty Pedagogického asistentství a Učitelství fyziky pro ZŠ na PdF MU v Brně. Tento text studenty seznamuje se základní fyzikální terminologií v anglickém jazyce a obsahově odpovídá úrovni fyziky a tématům probíraným v rámci předmětu fyzika na běžných základních školách. Učební text je členěn na tři základní části – soubor textů a cvičení, klíč k těmto cvičení a překladový slovníku základních fyzikálních pojmů. Cílem bylo vytvořit učební text, který by se dotýkal většiny oblastí fyziky. Tento cíl jsme naplnili, nicméně důsledkem je větší rozsah práce. Učební text je ve fázi, ve které je určen k samostatné práci studentů. Existuje zde možnost dalšího zdokonalení. Tím je převedení cvičení textů do elektronické podoby a vytvoření elearningového kurzu, například na platformě Moodle. Takový kurz by pak mohl být nabízen studentům Pedagogického asistentství a Učitelství fyziky pro ZŠ na PdF MU v Brně jako volitelný předmět.
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7. Citovaná literatura Herzlík, B. (1987). Anglické odborné texty pro fyziky. Brno: Univerzita J. E. Purkyně, Přírodovědecká fakulta Kirk, T. (2014). Physics for the IB Diploma. Oxford: Oxford University Press Pople, S. (2010). Complete Physics for IGCSE. Oxford: Oxford Univerzity Press Reynolds, H. (2013). Complete Physics for Cambridge Secondary 1. Oxford: Oxford University Press Thompson, A. & Taylor, B. N. (2008). Guide for the Use of the international System of Units (SI). Gaithersburg, MD: National Institute of Standards and Technology Tulajová, I. (2000). Physics: A Reader: intermediate level. Brno: Masarykova univerzita, Přírodovědecká fakulta Walker, J., Halliday, D., & Resnick, R. (2014). Fundamentals of Physics (10. vydání). Hoboken, NJ: Wiley
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8. Online zdroje Advanced Instructional Systems, Inc., & North Carolina State University (2010). Vernier Calliper. Dostupné z: http://www.webassign.net/labsgraceperiod/ncsulcpmech2/appendices/appendixD/appen dixD.html Amscope (2015). Binocular Laboratory Clinic Veterinary Compound Microscope. Dostupné z: http://www.amscope.com/binocular-laboratory-clinic-veterinary-compoundmicroscope.html Applect Learning Systems Pvt. Ltd. (2015). Spoon. Dostupné z: http://img1.mnimgs.com/img/shared/discuss_editlive/2191102/2013_01_09_09_16_58/i mage4246853015536859961.jpg Bashford, D. (1990). The Earth's magnetic field. Dostupné z: http://www.brad.ac.uk/archaeomagnetism/archaeomagnetic-dating/introduction-toarchaeomagnetism/magnetic-field/ BBC (2014). A stool in free stages of toppling. Dostupné z: http://www.bbc.co.uk/schools/gcsebitesize/science/triple_aqa/using_physics_make_thing s_work/moments/revision/4/ BBC (2014). Electric bell. Dostupné z: http://www.bbc.co.uk/bitesize/standard/physics/using_electricity/movement_from_elect ricity/revision/2/ BBC (2014). How to find the centre of gravity on one shape. Dostupné z: http://www.bbc.co.uk/schools/gcsebitesize/science/triple_aqa/using_physics_make_thing s_work/centre_of_mass/revision/1/ BioNinja (2016). The Greenhouse Effect. Dostupné z: http://www.ib.bioninja.com.au/standard-level/topic-5-ecology-and-evoluti/52-thegreenhouse-effect.html British Dam Society (2010). Cross-section through gravity dam. Dostupné z: http://britishdams.org/about_dams/gravity.htm Brownian motion. (2016). In Encyclopædia Britannica. Dostupné z: http://www.britannica.com/science/Brownian-motion CERN (2016). Badge logo. Dostupné z: http://design-guidelines.web.cern.ch/badge-logo Coffey, G. (2010). Atom Diagram. Dostupné z: http://www.universetoday.com/56469/atom-diagram/ Costa, D. (2015). Ionization Scheme. Dostupné z: http://inventorspot.com/articles/ionization_physical_process_many_useful_applications 160
Crystalinks (2016). Diagram of solar eclipse. Dostupné z: http://www.crystalinks.com/eclipse.html Electrical4u (2016). Fleming’s Left Hand Rule. Dostupné z: http://www.electrical4u.com/fleming-left-hand-rule-and-fleming-right-hand-rule/ Enter to Learn (2011). Electroscope. Dostupné z: http://www.desktopclass.com/notes/physics/electroscope-and-its-use-10th-physicslesson-15-3.html Excellup (2014). Bell Jar Experiment. Dostupné z: http://www.excellup.com/classnine/sciencenine/soundNCERTBookExerciseQuestionAndA nswer_1.aspx Fahrenheit temperature scale. (2016). In Encyclopædia Britannica. Dostupné z: http://www.britannica.com/science/Fahrenheit-temperature-scale Gibbs, K. (2013). The Magdeburg Hemispheres. Dostupné z: http://www.schoolphysics.co.uk/age1114/Matter/text/Magdeburg_hemispheres/index.html Hasselo, W. (2016). DC motor. Dostupné z: http://www.w-hasselo.nl/mechn/electricdrive/motoren/principle/comutator.html Inouye, B. (2016). Three Cubes. Dostupné z: https://manoa.hawaii.edu/exploringourfluidearth/physical/density-effects/densitytemperature-and-salinity Institute and Museum of History of Science (1999). Torricelli’s barometric experiment. Florencie, Itálie. Dostupné z: http://www.imss.fi.it/vuoto/eesper2.html JB Systems, Inc. (2011). Magdeburg Hemispheres. Dostupné z: http://www.jbii.com/VacuumPumps/Rietschle.htm Jeon, Ch. (2016) Physics of Maglev Train. Dostupné z: http://ffden2.phys.uaf.edu/212_spring2011.web.dir/Chan_Jeon/physics-of-maglve-train.html Jones, A. Z. (2008). Rigid Body. Dostupné z: http://physics.about.com/od/physicsqtot/g/RigidBody.htm Kelvin. (2016). In Encyclopædia Britannica. Dostupné z: http://www.britannica.com/science/kelvin Kneller, G. (1689). Portrait of Isaac Newton. Dostupné z: http://www.newton.ac.uk/about/art-artefacts/newton-portrait Král, A. (2008). Vodpor. Dostupné z: https://commons.wikimedia.org/wiki/File:Vodpor.jpg
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Leduc, M. (2016). Four Strokes. Dostupné z: http://www.globalspec.com/learnmore/motion_controls/engines_components/industrial _engines Locations North (2016). LED vs. CFL vs. Incandescent. Dostupné z: https://locationsnorth.com/incandescent-light-bulbs-stock-up-or-be-prepared-to-switch/ Mahalaxmi Bearing Co. (2016) Ball Bearing. Dostupné z: http://www.indiantradebird.com/ball-roller-bearing?cpid=ODkwMSw3LDEsNA== MJCdetroit (2008). GasCan. Dostupné z: https://commons.wikimedia.org/wiki/File:GasCan.jpg NASA (2015). The International Space Station. Dostupné z: http://www.space.com/16748international-space-station.html National Fluid Power Association (2015). What is hydraulics?. Dostupné z: http://www.nfpa.com/fluidpower/whatisfluidpower.aspx Nuclear Science in Society (2016). Chain reaction. Dostupné z: http://web3.naroomah.schools.nsw.edu.au/resources/ANSTO/about/about_neutron.htm Pass My Exams (2016). Seesaw. Dostupné z: http://www.passmyexams.co.uk/GCSE/physics/turning-effect-forces.html Pearson Prentice Hall, Inc. (2010). Temperature scales. Dostupné z: http://kastedu.weebly.com/temperature.html Physics World (2006). The internal structure of a vacuum flask. Dostupné z: http://www.hk-phy.org/energy/domestic/print/heat_is_print_e.html Pics About Space (2016). Solar System Planets In Order With Pluto. Dostupné z: http://picsabout-space.com/planet-in-solar-system-in-order?p=2# Röntgen, W. (1895). Hand mit Ringen. Dostupné z: https://commons.wikimedia.org/wiki/File:First_medical_Xray_by_Wilhelm_R%C3%B6ntgen_of_his_wife_Anna_Bertha_Ludwig%27s_hand__18951222.gif Sarony, N. (1893) Tesla Sarony. Dostupné z: https://commons.wikimedia.org/wiki/File:Tesla_Sarony.jpg Sherafat, H. (2016). Eye scheme. Dostupné z: http://www.thelondoneyeclinic.com/cataract.html Schott, G. (1664). Torricelian experiment. Dostupné z: http://www.imss.fi.it/vuoto/eesper2.html Team Strauss. Force Meter. Dostupné z: http://www.teamstraus.com/SchoolDaysBorder_files/Class%20Events/force%20meter.gif 162
Test Prep – Online (2016). Pulleys. Dostupné z: https://www.testpreponline.com/mechanical-pulleys.aspx TutorVista (2016). Formation of Image by a Plane Mirror. Dostupné z: http://www.tutorvista.com/content/science/science-ii/reflection-light/formation-planemirror.php TutorVista (2016). Torque. Dostupné z: http://www.tutorvista.com/content/physics/physics-i/forces/moments.php U.S. Naval Historical Center (1959). Bathyscaphe Trieste. Dostupné z: https://commons.wikimedia.org/wiki/File:Bathyscaphe_Trieste.jpg University of Waikato (2010). The three states of matter. Dostupné z: http://sciencelearn.org.nz/Science-Stories/Strange-Liquids/Sci-Media/Images/Threestates-of-matter Werneuchen (2008). Hydrostatisches Paradoxon. Dostupné z: https://en.wikipedia.org/wiki/File:Hydrostatisches_Paradoxon2.svg World Standards (2016). Plug & socket types. Dostupné z: http://www.worldstandards.eu/electricity/plugs-and-sockets/ Yzmo (2011). Heliumm atom QM. Dostupné z: https://commons.wikimedia.org/wiki/File:Helium_atom_QM.svg
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Příloha – Test fyzikální angličtiny Tento test je zaměřen na zjištění stavu znalostí z oblasti fyzikální angličtiny studentů Pedagogického asistentství fyziky pro ZŠ na PdF MU v Brně. Test a výsledky tohoto šetření budou použity v diplomové práci Angličtina pro fyziky. Výsledky testu jsou zcela anonymní. Děkujeme za spolupráci. 1. What are the names of these devices? Hint: you can choose from the box. inclined plane
lever
pulley
screw
Where would you locate load and effort? Mark them in both pictures.
2. Fill in the gaps in the article about forces. Use the words in the box. Sometimes you have to change them. attract charge
magnetic mass
pull down repel
touch weight
Different types of force The gravitational force is the force that attracts you to the Earth. It is also the force that attracts the Earth to you! The force of gravity acts between any objects that have ____. On Earth, the force of gravity on an object is called the object’s ______. This force acts towards the centre of the Earth. It always ______ you ____, whenever you are on the Earth. A different kind of force is an electrostatic force, which acts between objects that are charged. Rubbing plastic objects can ______ them up with static electricity. Once charged they can _______ or _____ other charged objects. Magnets attract magnetic materials such as iron, steel, or nickel. There is a ________ force between the magnet and the magnetic material. The objects do not need to be ________ to experience the force. It’s the same with gravitational and electrostatic forces. 164
3. Complete the table with the information about quantities related to electricity.
Symbol
Unit
Q
electric current
resistance
I
Unit Symbol
C
ampere
electroscope
A
U, V
V
R
Ω
voltmeter
4. Write the definition of Archimede’s principle. You can use the words in the box. act body buoy up buoyant force
displace equal fluid immerse
magnitude net force pressure submerge
surface tension upward volume weight
Archimede’s principle
5. Describe the image that is produced by a plane mirror.
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The Image is
6. Choose and solve one of the following problems. a. There is a glass tube, open at one end, filled with mercury. The length of the tube is 1 m. We turn it upside down and put the open end into the basin filled also with mercury as shown in the picture. Calculate the height to which the column of the mercury in the tube descends. The density of mercury is 13,545 kg/m 3 and the atmospheric pressure is 101,325 Pa.
b. There are two trains traveling at a constant speed. The first train started its journey at 5 PM and it was traveling at 50 km/h. The faster train started at 5:30 PM and it was traveling at 90 km/h. Determine how long did it take for the faster train to catch the slower one. Determine also the distance they had travelled until they met. Your option:
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