(Solved): In this activity, you will experiment with different ways of putting charge on an electroscope. You ...

In this activity, you will experiment with different ways of putting charge on an electroscope. You will create the charge by rubbing a nylon cloth against a PVC pipe. Nylon is higher than PVC on the triboelectric sequence, which means that rubbing them together will leave the nylon cloth positively charged and the PVC pipe negatively charged. 1. Charging by Direct Contact and Grounding (a) Rub the PVC pipe with the nylon cloth for about 15 seconds. (b) Touch the PVC pipe to the wire at the top of the electroscope and slide it back and forth along the wire to transfer charge to the electroscope. You should see the leaves of the electroscope swing apart and then stay separated. If the leaves do not separate, repeat steps (a)-(b). Why did the leaves separate? Answer below. (c) Move the PVC pipe away and touch the wire at the top of the electroscope with your hand. This provides a path for the excess charge to leave the metal and flow to the ground. This is called grounding the charge. What did the leaves do when you touched the top wire? Why? Answer below. 2. Charging by Induction (a) Again, rub the PVC pipe with the nylon cloth for about 15 seconds to charge it. (b) This time, bring the charged PVC pipe close to the wire on top of the clectroscope, but den't touch it. Once again, you should see the leaves of the electroscope swing apart and then stay separated. If the leaves do not separate, repeat steps (a)-(b). The PVC pipe has a negative charge, so it repels the electrons in the wire, forcing them down into the leaves of the electroscope. This makes the bottoen of the electroscope negatively charged and the top of the electroscope positively charged. This is called polarization - overall, the electroscope is neutral, but there has been a separation of the positive and negative charges. Physies 46 Static Charge Lab (c) Pull the PVC pipe away from the wire. What do the leaves do when you pull the pipe away? Why? Answer below. then stay separated. (c) While holding the charged PVC pipe in this position, touch the wire on top of the electroscope with your fingers. What happens to the leaves of the electroscope when you touch the top wire? Answer below. (d) Move your fingers away from the wire and the pull the PVC pipe away from the electroscope. What happens to the leaves of the electroscope when you pull the PVC pipe away? Is there any charge left on the electroscope? Answer below. (e) Now move the charged PVC pipe to the bottom of the electroscope. What happens to the leaves of the electroscope when you put the PVC pipe near the bottom? Answer below. (f) What is the sign of the charge on the electroscope (positive or negative)? How do you know? Answer below.