Video: Watch this demo
Description: This demonstration illustrates the fluid properties of granular systems.
- 2000mL Pyrex beaker
- Plastic beads
- Ping pong ball
- Metal ball similar in size to ping pong ball
- Fill the beaker with the plastic beads.
- Bury the ping pong ball in the bottom of the beaker so that it’s not visible.
- Put the ball bearing on top of the beads (see before picture).
- Shake the beaker around to “simulate” a fluid. Note: some up and down motion is necessary.
- After a little shaking, the ping pong ball will rise to the top of the beads and the ball bearing will sink into the beads.
- Explain that granular systems can act like fluids. In this case, when the beads shake, they are acting like a liquid: the denser ball will sink, and the less dense ball will rise to the top.