Bernouilli's principle: A simple DIY experiment explains how it works
Physics can get quite tricky for school-goers to fully comprehend when learnt only theoretically. Practical experimentation is the best way to not merely ensure clear understand of physics, but to also have fun with science. Here is a simple, DIY floating ping pong activity to help your kid understand a physics concept, known as Bernouilli’s principle.
Formulated by Daniel Bernouilli, the Bernouilli principle states that an increase in a fluid’s (liquid or gas) speed occurs simultaneously with a decrease in the static pressure or in the fluid’s potential energy. For example, when a truck drives past very fast, it creates a low pressure area around it. As a result, dust gets pulled along with the vehicle in this low pressure area.
What you will need
This simple experiment calls for only two materials which you can easily find lying around in the house.
- 1 ping pong ball
- 1 plastic straw (ensure that it is flexible)
Step-by-step guide
Gather all the materials and help your school goer follow these easy-peasy steps
- Bend the straw to a 90 degree angle.
- Hold it in one hand such a way that the shorter portion of the straw is at the end. Ensure that it is pointing up.
- Gently place the ping pong ball over this short end of the straw.
- Blow air into the straw. Simultaneously, slowly release your grip over the ball.
- You will notice that the ping pong ball will get suspended in the air. This makes it look like it is magically floating in thin air!
How exactly is the Bernouilli’s principle at work here?
As air is blown through the straw, it causes the ping pong ball to float, as witnessed in the activity. The ball stays in the air as a consequence of two fundamental reasons: 1. The air surrounding the ball pushes it in order to keep it afloat. This is similar to when a kite is flown in the sky. 2. The air pushed through the straw employees Bernouilli’s principle. Here, the air which is moving around the ball is located in an area of low pressure as compared to the usual, stationary air around it. When the air is blown through the straw, the ball is trying to escape the lower pressure area. However, the air in the higher pressure area (the stationary air) forces it back to the low pressure area, thus keeping it afloat.