1. Unit 16 Scientists at work The second period Zhang Jun

2. Benjamin Franklin 1706 ~~~ 1790 statesman, inventor printer, diplomat philosopher writer, scientist

3. 1.When did Benjamin Franklin do his experiment? 2.What was the purpose of this experiment? 3.What was needed in this experiment?What was needed in this experiment? In June 1752 To show that lightning and electricity were the same.

4. 4.What was the result of the experiment? Did it succeed? 5.Why is it better to make the kite of silk better than of paper? 6.What is the use of the silk ribbon? The electricity stored in the condenser can be used to do other experiments, which proved that lightning and electricity were the same. It will not tear so soon in weather with rain an strong winds. It will protect you from the electricity.

5. A kite experiment A kite A key Some really bad weather A condenser to store electricity

6. A kite Some wooden sticks A very sharp piece of metal A ball of string A piece of silk A silk ribbon

7. How to make a kite 1. Build the frame of the kite by making a small cross of two pieces of light wood. 2. Tie the corners of the handkerchief to the points of the cross. 3. Add a tail to the frame and tie a long string to the cross. What to do then  Fix a very sharp piece of metal, pointing a foot or more above the frame, 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, just above the key. Tie to Add Fix Fasten

9. key ribbon condenser shed

10. 1. Frankline attracted lightning by using a______made of________. 2. A silk kite does not attract lightning, so he had to fix a long sharp piece of______to the top of the longest stick of the cross. 3. He brought a ___________ to store electricity. 4. He used a small______in the fields to keep himself and his tools dry. 5. He tied a silk ______to the string so that the kite could protect him from the ___________. 6. He directed the electricity towards the condenser with a piece of metal at the end of the string by tying a metal _______to the end of the string. kite silk metal condenser shed ribbon key electricity

11. Aim : Materials: Instructions: Description: Result: FRANKLIN’S FAMOUS KITE EXPERIMENT

12. Aim : Materials: Instructions: Description: Result: To show that lighting and electric are the same. some wooden sticks, a piece of silk, some rope, a sharp piece of metal, silk ribbon, a key, a condenser, a small shed, a thunderstorm with lightning Paragraphs 5 & 6 Paragraph 3 The electricity can be collected and stored in the condenser; can be used to do other experiments; proves that lightning and electricity are the same.

14. When does lightning usually happen? outside When lightning happens, what should we not do? In summer, before and when it rains. inside *Make yourself lower than the things around you *Don’t stand under an isolated ( 孤立的） tree *Don’t get into the water(good conductor) Don’t be near the window or the wires of lights,telephones and so on. Benjamin Franklin