Mary Motion’s Spinning Bucket


To demonstrate the concept of centripetal force



  • Plastic bucket
  • Water


Put water in the bucket until it is three-quarters full. Make sure the bucket is not completely full!  Pick up the bucket by the handle. Starting with your arm at your side, turn it around in a sweeping motion. Make it move toward the sky, and then to the ground, in a windmill motion. You should make a complete circle with your arm. Be consistent with the speed and rotation.



The spinning bucket of water is a demonstration of centripetal force, the inward force acting on a rotating object. The water is falling at the same rate as the bucket is rotating. If you slow down the rotation of the bucket, you will get wet. This is because the water is falling faster than the rotating bucket. Practice this outside!