Activity 3...The Pith Ball 


You have found out about charge, charging objects, sparks and some simple devices. Here is the time to play with charge a little more and discover some new properties.


You will get a deeper understanding of the behavior of charges, how they move around and are transferred.


What to do?

Charge up a pith ball: Hang one of the pith balls on the stand. Charge the electrophorus the way you did in Activity 2. Touch the pith ball with the electrophorus. Now charge the clear rod with the white cloth and bring it near the ball. What happens? What charge do the objects have?





Touch the pith ball then recharge it with the electrophorus. What do you think is going to happen if you bring the charged golf tube near the ball? Try to predict. You should figure out the charge on the objects.

Test your prediction. Were you right?





Take both pith balls and hang them on the stand. Charge the electrophorus and touch the balls with it. Record your observations.





What happens? Think of the charges again.










Pith ball pendulum: Take a single pith ball and hang it up. Charge up the electrophorus and bring it slowly near the ball. Watch what happens. Now go ahead and touch the pith ball with the electrophorus. Hold the pan in place. What happens?






Touch the pith ball to discharge it. Charge up one of the electrophoruses and now take both the charged and the uncharged one and bring it near the ball on both sides as you see it on the picture.


Let the charged electrophorus touch the pith ball. What happens? Play with the pans making the separation smaller and larger.








Try to explain how this pendulum works. Remember the surface of the pith ball is painted with metallic paint.