【高一英语课件下载】franklin’s famous kite experiment.ppt

Questions Why did Franklin do this experiment? What happened during the experiment? What’s the results of the experiment? What do we need to do the experiment? How can you make a kite ? Why is it better to make the kite of silk than of paper ? What are the next three steps after you make a kite ? What should be paid attention to when it was being done? Instructions A small cross of two pieces of light wood. Tie the corners of a handkerchief to the points of the cross . Add a tail to the frame . Tie a long string to the cross. Fix a sharp piece of metal to the top of the longer stick of the cross. Fasten a key to the end of the long string. Tie a silk ribbon to the string. Connect a condenser to the end of the string. Discussion Do you think Franklin’s experiment dangerous ? Why? What can you learn from Franklin? * A brief introduction of Franklin Benjamin Franklin (1706～1790) 1.In 1752 scientists already knew what electricity was. 2.Franklin was helped by a friend to do the experiment. 3.Franklin made the kite of silk because wet silk does not conduct electricity 4.A condenser was used in the experiment to store electricity. 5.The key tied to the string was put into the door to stop the kite from flying away. True or False: F F T F T How can we make a kite? _____the _______of the kite by making a small cross of two pieces of_____ ______. The pieces should be just long enough to _____the corners of the handkerchief. ___ the corners of the handkerchief ___the points of the cross. ____a tail ___the frame and ___a long string____the cross so that you can ______the kite. Build frame light wood reach Tie to Add to tie to control paper wooden sticks string kite The next three steps are very important. First, ___a very sharp piece of ______,pointing a foot or more. Second,_______a key to the end of the long string. Third,____a silk ribbon ___the string, just above the key. This ribbon which must not____ ____,will________you _____the electricity.