I missed photographing our first forces of the universe experiment, but I’m glad I remembered this one!

Centripetal and Centrifugal Forces

Materials:

Small bucket on a string filled 2/3 full.

Predict:

What will happen when the bucket is swung upside down over your head?

Procedure:

Swing the full bucket over your head and see what happens.
Swing it slower and observe again.

Predict again:  What will happen when you let go while it is upside down?

Empty the bucket and let go when the bucket is overhead.

Scientific Explanation:

Centripetal force is the force provided by your arm, pulling the bucket in.  Centrifugal force is the force pulling the bucket out.  Since there is a force pulling the bucket & water in and a force pulling the bucket & water out, the water stays in the bucket.  When the arm stops pulling, the centrifugal force takes over and pulls the bucket in an arc away instead of falling straight down.

Recording:

For our experiments, Aidan has a scientific record sheet.  During the experiment, I simply have him write his predictions and then afterwards he fills in the procedure, observations, results, titles and dates the experiment, and signs it.