Rotating Ping-Pong Balls in Water

PIRA 1D52.33

Overview:

Bobbers are shown to move inward when rotated in water due to the fact they are not as dense as water.

Materials:

Rotating apparatus, two water filled jars.

Setup:

Position water filled jars on a counter. Hold the apparatus upside down and move the lids over the jars. Twist the jars until they are tightly fitted onto the lids. Carefully flip over so that the stand is on the table.

How to:

Spin the apparatus and see that the bobbers move inward.

Safety:

Do not spin faster than two revolutions a second.