unit 4 astronomy.ppt

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1、Unit 4 AstronomyLesson 2In the last lesson,we learned:how the earth _ _ of life on the earthWhat did we learn in period one?Quick RevisionQuick Revisioncame into being the evolutionin water The development of The development of plants and animalsplants and animals on land the arrivalof human beingsW

2、ater was foundamental to life.Howeverglobal warming 温室效应温室效应What happens as a result?Human beingsIf we keep destroying our earth,maybe one day we have to leave our mother earth and move to other planets!土星土星 Saturn天王星天王星Uranus金星金星Venus地球地球Earth 火星火星Mars 水星水星Mercury 木星木星Jupiter 海王星海王星Neptune Which pl

3、anet do you want to move to?too close to the suntoo far away from the suntoo hot to live intoo cold to live inMars may be a place to move toMaybe the moon is our next destination!OROR neither too close nor too far away from the sunLiving on Mars or on the moon Have you ever thought of living on othe

4、r planets like Mars or the moon?What is the difference between walking on the earth and walking on the moon?8Do you think that living on Mars or on the moon is the same as living on the earth?Q 1Q 2Q 3Watch the video clip to see what walking on the moon is likeLike floating/flying in the airFloating

5、 in the airThe moons gravity is lighter than the earths and people weigh less than on the moon.gravity rvti 重力重力gra-vi-ty If we want to live on other planets such as the Mars or the moon,we need to get some basic knowledge of the universe such as the force of gravity.Lets listen to the a dialogue to

6、 dig out something about gravity.Pre-listening Who are they?Scientists(past and present)studying the universe.They are what we called the astronomers strnm as-tro-no-merAll these three scientists study gravity.Issac Newton Albert Einstein Stephen HawkingNewtons gravity is about the earth.Einsteins g

7、ravity is about the relationship between time and universe.Hawkings gravity is about black holes.something you need to know The ideas of gravity have been changing and developing.Predicting/Guessing1.What is gravity?2.Who first put forward the idea of gravity?3.Which one has greater gravity,the sun

8、or the earth?4.What may happen to time in black holes?Does it go faster or slower?1.Well,at first people thought it was because the earth was _.Of course that was wrong.One day Isaac Newton _.He said that something else must be _ the _.He called it“_”.Part 1-Newtons idea on gravitythe centre of the

9、universepullinggravitywatched an apple fall to the groundapple back to earth2.They did.Later they worked out that _ _ has stronger gravity than _.If you are traveling in deep space,you couldnt _.Youre just too far away.objects(like the sun)bigger smaller objects(like our planets)fall back to the ear

10、th1.What is gravity?2.Who first put forward the idea of gravity?3.Which one has greater gravity,the sun or the earth?Gravity made everything fall back to the earth.Newton.The sun,because bigger objects have stronger gravity than smaller objects.In 1905 Einstein said that in space large _ make space-

11、time bend;the _ the object,the _ space-time bends.So time goes _ in very strong gravity.objectslargerfurtherslowerPart 2-Einsteins idea the theory of relativity 相对论Theoretically,time goes faster on the moon than on the earth.MJ:What about black holes?LY:Thats a place in space which has such a strong

12、 mass(质量质量)that _ _.There is a kind of edge around this mass.If you cross over this edge（边缘）（边缘）around this mass,its _ _.However,if you dont cross this edge,you can _.Stephen Hawking has done a lot of research into black holes.He has shown that they“spit”things out as well as“eat”them.nothing can es

13、cape from its impossible for you to still escapePart 3-Hawking ideagravityget backTrue or FalseThose lights at the edge of“black hole”can escape it?()The gravity in the black hole is the greatest.()3.Time goes slower in black holes.()Checking1.What is gravity?2.Who first put forward the idea of grav

14、ity?3.Which one has greater gravity,the sun or the earth?4.What may happen to time in black holes?Does it go faster or slower?destruction to the earthMoving to other planets such as the moonknowledge about gravitythe first person to put forward a theory about gravitysuggested in 1905 that gravity wa

15、s different in spacehas used Einsteins ideas to make ideas about strange things called“black holes”NewtonEinsteinHawking Summing upaurorafarmlandplainwild animalsthe beauty of our earthIts our duty to protect the environment.riveroceanAssessmentPoints54321I get some knowledge about gravity.I am able to put what I hear into my own words.I am involved in the whole lesson.I am not distracted by the speakers personal habits and the noise in the classroom.