Materials Required:
l Bath spray hose
l Funnel
l Bathtub faucet
l Ping-Pong ball
The help of one of your parents
Procedure:
- Ask one of your parents to remove the spray head from a bath spray hose, then insert the narrow end of the kitchen funnel into the hose opening.
- Connect the other end of the hose to the bathtub faucet. Hold the funnel so that it points downward into the tub, and turn on the water.
- Push a Ping-Pong ball into the funnel as far as you can. Take your hand away. The Ping-Pong ball will not be pushed out, but rather will stay securely in the funnel. If you turn the water on faster, the ball will only cling more firmly.
This Is What Happens:
The stream of water rushing from the hose into the funnel produces an area of low pressure between the funnel and the Ping-Pong ball. The air pressure outside the funnel pushes upward on the ball and supports it against the downward thrust of the water. This experiment is a good example of Bernoulli’s principle: The pressure in a flowing stream of liquid or gas is less than at its sides.
