A curved tube with two balls inside can be rotated. With the tube filled with water, the balls float out at the ends. When the apparatus is spun, the balls descend to the center. (as the more dense water is pushed to the outside.)
NOTE: be sure the stoppers are tight before spinning!
When dry, the balls rest at the center when apparatus is at rest. Then when spun, the balls are flung to the outside.
Questions:
Would this work on the moon? (ie. with lower gravity?)
Would changing the density of the liquid change the results?
