How to Do Bernoulli's Theorem Experiment With a Plastic Bottle

Basically, Bernoulli's theorem states that in areas where air moves rapidly, pressure is low. This explains how airplanes fly and how curveballs work. Another way to think about it is that water moves faster through a narrow section of pipe than through a thick section. One great way to explain Bernoulli's theorem is with a plastic bottle and a ping-pong ball.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Plastic bottle
• Scissors
• Ping pong ball

1. Take a soda or water plastic bottle and mark a line all around the bottle.

2. Cut the bottle about two to four inches from the top of the bottle, along your line. Be careful not to cut yourself as you cut the bottle. Once you've completely cut around the plastic bottle, you have a cup with a funnel on the end of it.

3. Pick up a lightweight ping-pong ball and demonstrate how light it is. You can weigh it, blow it out of your hands or off a table, and even bounce it up in the air.

4. Put the ping-pong ball into the cup and try to blow the ping-pong ball out of the cup using your mouth. Because of Bernoulli's theorem, you won't be able to, despite the lightness of the ping-pong ball.

Tips & Warnings

• Because plastic bottles are so cheap, this is a cheap experiment to do. If you're doing this experiment with a large group, using lots of bottles will also help stop the spread of germs.