Unit16-sicentists at work PPT课件.ppt

Make a small cross
Make a kite
Tie a long string
Fix a very sharp piece of metal
Fasten a key to the end of the string
True or False
In 1752 scientists already knew what
electricity is .
T
Franklin was helped by a friend to do the
experiment.
F
Franklin made the kite of silk because wet silk
does not conduct electricity.
• He had to direct the electricity towards the condenser • He tied a metal key to the end of the string.
Homework
• Read the text at least five times, and retell how to do Franklin’s famous kite experiment.
Conclusion The experiment proves that lightning and electricitybon to the string
Build the frame of the kite
Tie the corners of the handkerchief
• He had to stop the kite from flying away, without touching the string that would be charged with electricity
• He tied a silk ribbon to the string that he kept dry.
F
A condenser was used in the experiment to
store electricity.
T
The key tied to the string was put into the door
to stop the kite from flying away.
F
Discussion
• Finish the exercise of Word Study on P 26
• Finish the exercise of Unit 16 in EB A.
• 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
• He attracted lightning by using a kite. • A kite made of paper won’t last long in rainy weather
• His kite was made of silk. • A silk kite doesn’t attract lightning • He fixed a sharp piece of metal to the top of the longer stick. • He had to collect and store the electricity • He brought a condenser. • He had to make sure that he would not be hit by the lightning • He used a small shed in the fields.
Experiment’s name Kite Experiment
Purpose
Time Result
To show that lightning and electricity are the same
In June 1752
The string was getting charged, “I” collect and store a great deal of electricity in the condenser.
Franklin’s Famous Kite Experiment
The main idea of each part
Part 1 Para 1 to Para 3 Brief introduction about the
purpose and result of kite experiment. Part 2 Para 4 to Para 6 How to make the kite and how to do the experiment.