Unit 4 Astronomy: the science of stars教案

a. page 27. first let students finish part 1,2
b. check the answers with the whole class.
c. give students 3minutes to finish part 3.
d. let the students read part 4 for a while and finish it.
e. turn to page 63. first let the students finish 1and 2 and check the answers.

step ⅲ preparation
show some sentences on the blackboard.
a. a tree has fallen across the road.
b. you are a student.
c. to find your way can be a problem.
d. smoking is bad for you.
e. “how do you do?” is a greeting.
f. what she said is not yet known.
g. that we shall be late is certain.
h. it’s certain that we shall be late .

t: what part does the underlined part serve as in each sentence? or find its subject in each sentence.

step ⅳ grammar
1. give the students some time to find the sentences in the passage. the collect answers from the class.
2. show typical examples of how to make a subject clause. guide the ss to find out what changes we have to make when we make a sentence or combine two sentences using subject clause. teacher shows the example and ss write down the sentences.
3. turn to page 64. read the following passage quickly and finish the eight sentences.
4. have a discussion in pairs. the topic is my dream. one talks about the problems in his study or life, another gives some advice. remind the students to use the following structures
a. my problem is…
b. my trouble is…
c. the question is…
d. my advice is…
e. what i think about it is…
f. the fact is…
g. my suggestion is…

step ⅴhomework
1. finish part 3(p23)
2. finish part 3(p64)

added material:
什么是黑洞？
就是在宇宙中有那么一些點，這些點的體積趨向于零而密度變得無窮大，由于具有強大的吸引力，物體只要進入離這個點一定距離的范圍內，就會被這個強大的引力吸收掉，連光線也不例外。因此任何進入這個范圍的物體都無法再逃出來，就是說，沒有任何信號能夠從這個范圍內傳出，因此這個范圍的界限被稱作視界，里面的情形人類無法看到。所以科學家給它起了個名字叫黑洞，英文就是black hole。 一顆燃燒盡了的恒星由于自身的重力而不斷坍縮，最后就會形成黑洞。
歷時30年霍金改觀點 稱黑洞能“吸”能“吐”
從事宇宙黑洞研究近三十年的世界天體物理學泰斗斯蒂芬•霍金在前不久承認“黑洞悖論”有誤之后，21號，他在愛爾蘭都柏林舉行的一個學術研討會上終于就自己的新發現向外界進行了詳細闡述。
黑洞是宇宙中引力極強的區域。19世紀70年代，霍金首次提出黑洞能夠輻射能量的理論，但是在引入這一理論的同時，霍金也制造了物理學上的一個巨大難題，因為他認為
黑洞輻射不包含以前吸入物質的相關信息，而且隨著黑洞的消失，曾經存在的黑洞的相關信息也會消失于無形。這與量子力學中認為物質信息不會完全消失的理論相矛盾。對此，過去近30年來，霍金的解釋是：黑洞中的量子運動是一種特殊情況，這種說法受到了許多科學家的質疑。