浙江省杭州市塘栖中学高中英语必修三Unit4：listening2教学课件.ppt

Listening;Pre-listening ; 经典物理学理论体系的建立者。 1665年创立微分；1666年开始研究积分。 1666年,开始想到研究重力(gravity)问题，苹果落地的传说，也是在此时发生的轶事。其一生的重大科学思想是在这两年期间（22至23岁）岁形成的。1669年，把《自然哲学的数学原理》，《宇宙体系》)等手稿送到剑桥大学图书馆收藏。晚年研究宗教。;Albert Einstein（1879～1955）; 质量(m)和能量(E)的相当性：E＝mc2 爱因斯坦在量子论、分子运动论、相对论(Theory of Relativity)等物理学的三个不同领域取得了历史性成就，特别是狭义相对论的建立和光量子论的提出，推动了物理学理论的革命，他对社会进步事业也有重要贡献。;霍金 born in 1942 ; 斯蒂芬·藿金是当今科学界的一位传奇性人物。这不仅仅因为他是一位被誉为继爱因斯坦后最著名的科学思想家和最杰出的理论物理学家，还在于他是在常人无法想象的身体状况下进行研究和创造性工作的。;black hole 黑洞 ; 黑洞并非只是吞噬物质。除了会在星系形成的过程中扮演重要角色外，在经过一段相当漫长的时间后，黑洞也会把一些曾被它吸入的物质信息向外界释放出来。;Listening ;;;THEORIES OF GRAVITY ;Part 1 MJ: Hello, Dr Li Yanping. It’s so good of you to talk to me . Some students ask us why things always fall back to earth if you throw them up in the air. Could you explain it?;LY: Well, at first people thought it was because the earth was the centre of the universe. Of course that was wrong. One day lsaac Newton watched an apple fall to the ground. He said that something else must be pulling the apple back to Earth. He called it “gravity”.;MJ: I see. Did people accept his idea? LY: They did. Later they worked out that bigger objects (like the sun) have stronger gravity than smaller in deep space, you couldn’t fall back to the earth . You’re just too far away. ;Part 2 ;LY: Not exactly. You may pass it very fast and then it would throw you out into space again. After that you would slow down to the usual speed. MJ: How do you know this? LY: In 1905 Einstein said that in space large objects make space-time bend; the larger the object, ; the further space-time bends. So time goes slower in very strong gravity. MJ: What a bout black holes? LY: That’s a place in space which has such a strong mass that nothing can escape from its gravity. There is a kind of edge around this mass . ;If you cross over this edge around this mass. If you cross over this edge, it’s impossible for you to get back. However, if you don’t cross this edge, you can still escape