“Come to me.”
“Go that way. I command you.”
“Turn in a circle.”
Have you ever wished for a magic wand? You know the type. You can use it to command the movement of all sorts of objects. Well, in this activity, you’ll have a chance to build this type of wand. The “magic,” however, is hidden in the invisible field of electric charges.
Things Required:
Table tennis ball
Plastic pen
Wool
Directions:
Set the table tennis ball on a flat surface. Steady it so that it may not move.
Stroke the plastic pen with the wool. After stroking the pen, move it close to the table tennis ball. What happens?
Try moving the pen so that the ball may move with a continuous motion. Can you do it?
This Is What Happens:
As the pen was stroked with the wool, negative charges were transferred between the materials. These charges left the wool and accumulated on the pen. The pen became negatively charged.
When the negative pen was placed near the table tennis ball, its electric field affected the charges of the ball. The nearby negative charges were repelled by the pen and moved away. This left a relatively positive side of the ball. This positive side and the negative pen attracted. Once inertia and friction were overcome, the ball began moving.
