Description
This illustrates the concept of centripetal force and how it allows an object to move in a circular path without spilling. In this setup, a pail of water is swung in a vertical circle. As the tray moves, the water remains in the container due to the inward centripetal force acting on it, which is provided by the tension in the string or the person holding the tray.
When the tray reaches the top of its motion, the force of gravity is directed downward, but as long as the centripetal force is greater than or equal to the gravitational force, the water will stay in the pail. This demonstration visually reinforces the principles of circular motion, specifically how an inward force can keep an object in motion along a curved path, even when gravity is present. It also helps students understand the relationship between velocity, radius, and centripetal force.
Aliases
Greek waiter, Pail of water on Greek waiter, pail of water, waiter tray
PIRA DCS Number
1D50.40
Preparation Time
1 minute
Preparation & Instructions
Remove the lid from the jar and place it on the waiter tray. Swing it around in a vertical circle. Almost any method of swinging will work as long as the motion is smooth. Slow down gradually to bring it to a stop.