1) If you don’t have aa ping-pong ball with a dent or indentation in it, then use your thumb and make a small indentation.
2) Then place ping pong ball in a galls nearly full of water.
3) Turn on microwave for 1 minute
4) Using a oven mit remove the glass. Be careful as the water will be very hot. Remove ping pong ball and Observe.
Science behind this experiment
As the ping pong ball is heated, the air inside will be heated as well. As the molecules of air are heated, they will begin moving faster. AS they move faster, they will collide more frequently with the inside walls of the ping pong ball.
This will cause the ping pong ball to expand back to its original shape and volume. This is in accordance with Charles’ Law, which states that as the temperature of gas increases, its volume increases.