Bucket of Water

Concept Overview

Forces on a body in circular motion in a vertical plane.

Lecturer Procedure

Steps to Follow

1. Fill bucket approximately half-way with water.
2. Hold bucket by the rope
3. Swing bucket in vertical circle

Expected Result

Water will not come out of bucket.

Special Note:

Be sure to practice this prior to the lecture.  If the bucket is swung too slowly, water will spill out all over the floor and lecturer.

Historical References; Taken from original work of Percy H. Carr, 1970 

“If a pail partially filled with water is slung with sufficient speed over the head, the weight of the water is not sufficient to supply the force necessary to make the water move in such a highly curved path and the bottom of the pail will push on the water. The water cannot fall out. The same experiment can be performed with a glass tumbler.”