Unit4(精品).ppt

《Unit4(精品).ppt》由会员分享，可在线阅读，更多相关《Unit4(精品).ppt（51页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、Unit4:EnergyScience能源能源 Task1:whatenergydoyouknow?l gasoline l-petroleum(oil)wind power gasoline solar power coal geothermal heat biomass natural gas nuclear power water power electricity Task2:listtherenewableenergyandnon-renewableenergyrenewable energy:n-non-renewable energy:n n-Question:Whatisfos

2、silfuel?l petroleuml coal l natural gas Question:Howisfossilfuelformed?l Millions of years ago,the remains of plants and animals decayed and built up in thick layers.This decayed matter from plants and animals is called organic material-it was once alive.Over time,the mud and soil changed to rock,co

3、vered the organic material and trapped it beneath the rock.Pressure and heat changed some of this organic material intocoal,some into oil(petroleum),and some into natural gas.The main ingredient in natural gas is methane,a gas composed of one carbon atom and four hydrogen atoms.Petroleum(crudeoil)wh

4、at fuels are made from crude oil?u gasoline 汽油u diesel 柴油u-ProductsMadefromaBarrelofCrudeOil(Gallons)Petroleum(Oil)-AFossilFuelHowWasOilFormed?WhereDoWeGetOurOil?WhatFuelsAreMadeFromCrudeOil?-gasoline,diesel,&propaneHowDoesOilImpactTheEnvironment?energycalculatorlinkspagerecentstatisticsDidyouknow-c

5、rudeoilcanbesweetorsour?HowWasOilFormed?Oilwasformedfromtheremainsofanimalsandplantsthatlivedmillionsofyearsagoinamarine(water)environmentbeforethedinosaurs.Overtheyears,theremainswerecoveredbylayersofmud.Heatandpressurefromtheselayershelpedtheremainsturnintowhatwetodaycallcrudeoil.Thewordpetroleumm

6、eansrockoiloroilfromtheearth.WhereDoWeGetOurOil?The worlds top five crude oil-producing countries are:Saudi Arabia 沙特阿拉伯Russia United States Iran 伊朗China HowDoesOilImpactTheEnvironment?lExploring and drilling for oil may disturb land and ocean habitats.lIf oil is spilled into rivers or oceans it can

7、 harm wildlife.lHarmful gases from cars and trucks:carbon dioxide,carbon monoxide,nitrogen oxides,sulphur dioxide.These gases cause global warming and acid rain.Coal How coal is used?l heat our homel cooking l generate electricity Coalandtheenvironmentcarbon dioxide,sulfur,nitrogen oxide(NOx),and me

8、rcury When coal is burned as fuel,it gives off carbon dioxide,the main greenhouse gas that is linked with global warming.Burning coal also produces emissions,suchas sulfur,nitrogen oxide(NOx),and mercury,that can pollute the air and water.Sulfur mixes with oxygen to form sulfur dioxide(SO2),a chemic

9、al that can affect trees and water when it combines with moisture to produce acid rain.Emissions of nitrogen oxide help create smog,and also contribute to acid rain.Mercurythat is released into the air eventually settles in water.The mercury in the water can build up in fish and shellfish,and can be

10、 harmful to animals and people who eat them.NaturalgasHow natural gas is used?u Home useu industry HowDoesNaturalGasImpacttheEnvironment?l Natural gas burns more cleanly than other fossil fuels.It has fewer emissions of sulfur,carbon,and nitrogen than coal or oil,and when it is burned,it leaves almo

11、st no ash particles.l emit carbon dioxidel affect the environment when it is produced,stored and transported.It is made up mostly of Methane.Geothermalenergy地热地热l What is geothermal energy?Geothermal energy is heat from within the earth.We can use the steam and hot water produced inside the earth to

12、 heat buildings or generate electricity.Whereisgeothermalheatfound?l volcano火山火山l hotspring温泉温泉Usesofgeothermalheatl direct use:use hot mineral springs for bathing,cooking and heating.Today,many hot springs are still used for bathing,and many people believe the hot,mineral-rich waters have natural h

13、ealing powers.l generate electricity .Biomass生物能生物能lWhatisbiomass?Biomass is organic material made from plants and animals.Biomass contains stored energy from the sun.Plants absorb the suns energy in a process called photosynthesis（光合作用）.The chemical energy in plants gets passed on to animals and pe

14、ople that eat them.Howbiomassisused?l burning wood l landfill gas and biogas l biofuelsethonol（乙醇）and biodiesel （生物柴油)Biofuels are usually blended with the petroleumfuels-gasoline and diesel fuel.Ethanol is an alcohol fuel made from the sugars found in grains,such as corn,and wheat,as well as potato

15、 skins,rice,sugar cane.Biodiesel is a fuel made with vegetable oils,fats,or greases.Hydrogen氢氢What is hydrogen?Hydrogen gas is lighter than air and,as a result,it rises in the atmosphere.This is why hydrogen as agas(H2)is not found by itself on earth.It is found only in compound form with other elem

16、ents.Hydrogen combined with oxygen,is water(H2O).Hydrogen combined with carbon,forms different compounds such as methane(CH4),coal,and petroleum.It is also an abundant element in the earths crust.How Is Hydrogen Made?Because hydrogen doesnt exist on Earth as a gas,it must be separated from other ele

17、ments.Hydrogen atoms can be separated from water,biomass,or natural gas molecules.lmethane 甲烷l water l methanol 甲醇Howishydrogenused?l rocket,space shuttle l fuel cell 燃料电池The National Aeronautics and Space Administration(NASA)is the primary user of hydrogen as an energyfuel;it has used hydrogen for

18、years in the space program.Liquid hydrogen fuel lifts NASAs spaceshuttles into orbit.Hydrogen batteries,called fuel cells,power the shuttles electrical systems.The onlyby-product is pure water,which the crew uses asdrinking water.Text A:Fuel for the Future Summary1.What are features of fuel cell?2.W

19、hat is“indirect method”and“direct method”?3.What devices can be powered by fuel cell?4.What are consumers reaction to fuel cell?Whatareproblemsofusingfuelcelloncars?nHigh cost.Difficult to get from water.Hydrogen has to be stored at very low temperaturenDangerous.Hydrogen is explosive.nProduction.Ho

20、w to get hydrogen?Using fossil fuel?No Translationtask1.Whether they are used to run cars and buses or to make electricity for other applications,fuel cells operate by converting hydrogen to electricity without combustion.无论是用来启动轿车、汽车或者是用来发电，燃料电池工作时无需燃烧就将氢转化为电能。2.While batteries alone havent supplie

21、d the performance most drivers want,proponents believe that fuel cells,probably combined with batteries,hold the promise of performance,range and better mileage,compared with todays internal combustion engines.3.The direct method,which could be available commercially in five or six years,would use d

22、ifferent,lighter stacks of plates that eliminate the need for a reformer.五、六年后就可能会有直接方法。这种方法使用不同的、更轻的电解板，不需要转换装置。4.Marsh envisions fuel cells in lawn mowers,snow-blowers,jet skis and other mobile devices which now contribute to noise and air pollution,and which dont run well on batteries.Marsh 设想，燃料

23、电池可以用在割草机、吹雪机喷射滑橇和其他移动设备上。这些设备产生噪音和空气污染，并且用普通电池效果不好。5.Cars with methanol fuel cells would do little to change the regular routine of consumers at the filling station.使用甲醇燃料电池不会改变消费者们去加油站加油的习惯。Topics1.What is fossil fuel?What impact they have on environment?2.Talk about fuel cell3.Talk about the ener

24、gy you know4.What have you learned in this unit 活动形式活动形式n 小组间交流n一人做主题发言n 小组成员对话n 单词听写注意：1.鼓励用PPT讲述，列出重点内容 2.活动形式不限，鼓励创新，自由发挥 3.活动目的在于每个人参与quiz1.Most of the energy we use originally came from a)the sun b)the air c)the soil d)the oceans 2.Electrical energy can be produced from a)mechanical energy b)ch

25、emical energy c)radiant energy d)All of the above 3.Coal,petroleum,natural gas,and propane are fossil fuels.They are called fossil fuels because:a)they are burned to release energy and they cause air pollution b)they were formed from the buried remains of plants and tiny animals that lived hundred o

26、f millions of years ago c)they are nonrenewable and will run out d)they are mixed with fossils to provide energy 4.Gasoline is produced by refining which fossil fuel?a)natural gas b)coal c)petroleum d)propane 5.Global warming focuses on an increase in the level of which gas in the atmosphere?a)ozone

27、 b)sulfur dioxide c)carbon dioxide d)nitrous oxide 6.Solar,biomass,geothermal,wind,and hydropower energy are all renewable sources of energy.They are called renewable because they a)are clean and free to use b)can be converted directly into heat and electricity c)can be replenished by nature in a sh

28、ort period of time d)do not produce air pollution 7.In a nuclear power plant,uranium atoms a)combine and give off heat energy b)split and give off heat energy c)burn and give off heat energy d)split and give off electrons 8.Electricity is the movement of a)atoms b)molecules c)electrical power d)neutrons 中子referencehttp:/www.eia.doe.gov/kids/energyfacts/sources/whatsenergy.htmlhttp:/claweb.cla.unipd.it/home/mcanapero/hydrogen.htm