Filename: Induced Charge: Electrophorous

Electricity and Magnetism

Name: Induced Charge: Electrophorous

Location:  L314

Equipment:  Electrophorous Apparatus, Animal Fur

Suggested Presentation:  Rubbing the insulator Teflon material with the animal fur will cause it to become negatively charged. Placing the metal plate on top of the Teflon will induce the negative charges to move to the top of the metal plate. Touching the top of the plate with your finger will send the negative charges to ground, causing the metal plate to become positively charged.  Charge an electroscope with the metal plate and show that the electroscope is positively charged.  

Alternative:  To display the charges moving, touch the metal plate with a Neon Gas Discharge tube.  The tube will flash when the negative charges go to ground.  Lift the plate off of the Teflon and touch the plate with the gas tube, and it will again flash when the negative charges travel from ground and go back onto the positively charged plate, neutralizing the plate.