COOL Experiments for Kids

(printable version)

How do Satellites Stay Up?

This experiment will show you the different forces like those that keep a Satellite in orbit around the Earth.

Here's what you need:

• Ping-Pong ball
• Scotch tape
• Rubber band

Here's what to do:

Cut the rubber band so it's one long piece. Now tape one end to the Ping-Pong ball.

Slowly swing the Ping-Pong ball with the rubber band in a circular motion. Not the distance from your hand.

Increase the speed of the circular swing, again noting the distance. Be careful not to hit anyone or anything!

What's going on:
As the ball moves, it revolves at a certain distance. As the speed is increased, the ball moves and an increased distance. There are two forces acting on the Ping-Pong ball. One is the fore of gravity which tends to pull the ball to the center of the earth. The second is the centrifugal force which forces the ball away from your hand. When these two forces are balanced, the ball will revolve at the same distance. This is how satellites work. Gravity pulls the satellite down to earth; and at the same time, centrifugal force pulls the satellite away from earth. These two opposite forces keep the satellite up in space.