高一英语第十六单元富兰克林著名的风筝实验.pptVIP

Pre-reading Look at the pictures. Who are they? Are they famous? What are they famous for? Exercise 3 The pictures below show how Franklin did his experiment. Pick out the correct ones. Discussion Do you think Franklin’s experiment was dangerous? List the difficulties that Franklin met when he was doing the kite experiment How did Franklin solve these problems? It is difficult to go and look for lightning A kite made of paper won’t last long in rainy weather A silk kite doesn’t attract lightning He had to collect and store the electricity He had to make sure that he would not be hit by the lightning He had to stop the kite from flying away, without touching the string that would be charged with electricity He had to direct the electricity towards the condenser Summary In order to show that lightning and electricity are the same, Franklin built a strong kite .When the bad weather came, he did his experiment by using his kite and condenser. He found that the string was getting charged and he could feel a light but very clear electric shock. So he store much electricity in the condenser.This experiment proved his idea. To do this experiment ,four objects are needed :a kite ,a key , some bad weather and a condenser.Then the next three steps are very important.First, fix a very sharp piece of metal. Second, fasten a key to the end of the long string.Third, tie a silk ribbon to the string. a handkerchief string a key a silk ribbon two pieces of light wood a sharp piece of metal (one foot or more) What do we need to make the kite? 1.build the frame by making a small cross 2.tie the corners to the points of the cross 3.add a tail to the frame 4.tie a long string to the cross 5.fix a sharp piece of metal to the top of the longer stick 6.fasten a key to the end of the long string 7.tie a silk ribbon to the string above the key How to make Franklin’s kite? tail Functions Things needed Frank