1. CHARGING BY INDUCTION

2. Learning Goals ■I will be able to show/explain how to temporarily and permanently charge an object by induction.

3. What is it? ■Charging neutral object by bringing another charged object close to but not touching it.

4. Consider the following … ■The balloon: –When rubbed on sweater it developed a negative charge. –When brought near wall it pushed negative charges away (induced charge separation) –Balloon stuck because of law of electric charges.

5. We did this already … ■Ebonite rod and Cheerios lab! –Negatively charged ebonite rod –Neutral Cheerios –Ebonite rod brought close to Cheerios –Neutral Cheerios attracted to Negative Ebonite Rod

6. Charging Permanently by Induction ■Through induction, we can induce a permanent charge on an object. ■We can either force a positive charge on an object, or a negative one.

7. 12 3 45 Permanently Inducing a Positive Charge Step Description 1 Neutral electroscope. 2 Negative balloon induces charge separation in electroscope. 3 Ground “wire” attached, electrons flow from electroscope into ground. 4 Ground wire is removed 5 Charges spread out evenly, electroscope is positively charged

8. Permanently Inducing a Negative Charge ■Use the white board to demonstrate this!

9. 12 3 45 Permanently Inducing a Negative Charge Step Description 1 Neutral electroscope. 2 Positive balloon induces charge separation in electroscope. 3 Ground “wire” attached, electrons from ground attracted to positive side of electroscope. 4 Ground wire is removed 5 Charges spread out evenly, electroscope is negatively charged

10. Learning Goals Revisited ■I will be able to show/explain how to temporarily and permanently charge an object by induction.

11. Your Turn … ■P.489 #2,3,6