Density of Balls in Navy Beans

This is a fun demonstration for explaining the concept of density. It requires a plastic container, filled halfway with navy beans. The container is located in room 202, the lecture prep demonstration room, on the floor beneath shelf F.

 

The plastic container has a Ping-Pong ball at the bottom of the beans (if you so wish, this can be initially kept from students) and a denser black ball visible on top. If the ping pong ball is not at the bottom of the beans, push it down to the bottom.

The instructor should ask a student to vigorously shake the container. Students will watch the dense black ball sink to the bottom. After some time, the Ping-Pong ball emerges on top (to the surprise of the students).