Floating Ping Pong Balls
Gravity is a mysterious thing. We experience its effect every day but never really think about it. Not enough gravity and we’d be floating around in space. Too much gravity and we’d be flattened like a pancake. Luckily, the gravitational pull is just right here on Earth. It keeps us comfortably anchored to the ground. Still, it helps to understand that with regards to gravity, there are opposing forces at work.
- Turn hair dryer on highest setting
- Point hairdryer upward so air is blowing straight up
- Gently place ping pong ball above the hair dryer
The ping pong ball will float about the hair dryer, spinning and bobbing gently, but will not fly out of the air stream. The moving column of air produced by the hair dryer causes an area of low pressure (due to the Bernoulli Principle as explained below). The pressure in the column of air is lower than the pressure outside of the column of air. The ball cannot move into the area of the higher-pressure air. When it moves in that direction, the higher air pressure pushes it back into the low-pressure column of air. Hence, it floats above the hair dryer and does not fly across the room.
The Bernoulli Principle (or Bernoulli Effect)
A principle demonstrated in this experiment is the Bernoulli Principle. The Bernoulli Principle is a fundamental principle in fluid dynamics that explains the relationship between the pressure and speed of a fluid, such as air or water, moving through a pipe or over a surface. The principle is named after Daniel Bernoulli, a Swiss mathematician who first formulated it in the 18th century.
According to the Bernoulli Principle, as the speed of a fluid increases, its pressure decreases. This means that if a fluid is flowing through a pipe and the diameter of the pipe decreases, the speed of the fluid will increase, and its pressure will decrease. Conversely, if the diameter of the pipe increases, the speed of the fluid will decrease, and its pressure will increase.
The Bernoulli Principle has many practical applications, including in the design of aircraft wings, where it helps to create lift by increasing the speed of air flowing over the curved surface of the wing. It is also used in the design of car engines, where it helps to improve fuel efficiency by increasing the speed of air flowing into the engine.
Gravity comes into play when examining how high the ball goes before it gently bobs back down. The hair dryer pushes the ball upward until its upward force equals the force of gravity that is pushing down on it – that’s where it stays.
Required supplies for the floating Ping Pong Balls experiment
Supplies: Ping pong ball, Hair dryer
In-Article Image CreditsPing Pong Balls via Wikimedia Commons by Dean Hochman with usage type - Creative Commons License. November 9, 2015
Featured Image CreditPing Pong Balls via Wikimedia Commons by Dean Hochman with usage type - Creative Commons License. November 9, 2015