What Happens When You Blow A Ping Pong Ball Through a Funnel? Frugal Friday.

What Happens When You Blow a Ping Pong Ball Through a Funnel?

Ping Pong Balls

With simple materials around the house, you can help your grandchildren understand why airplanes fly.

How Is a Ping Pong Ball Different From a Flame?

We discovered in an earlier post, Can You Blow Out a Candle with a Funnel, that you can blow out a candle with a funnel, depending on which way the funnel is pointed.

That is, you can use the narrow end of the funnel to concentrate your breath and blow out a candle if you blow through the larger end, but not the other way around.

How about if you blow through the funnel and try to blow a ping pong ball up in the air?

The Experiment

You will need:

A funnel
A ping pong ball

Make sure the narrow end of the funnel is clean, because you will be blowing on it.

First, think about what you expect to happen.

Will you be able to keep the ping pong ball in the air by blowing through the funnel?

Put the ping pong ball into the wider end of the funnel
Keep the funnel upright so the ping pong ball will not fall out
Blow through the narrow end of the funnel.

What Happened?

You could not blow the ping pong ball into the air.

In fact, it seemed to hug the inside of the funnel.

Why?

It’s Bernoulli’s principle at work again. This is the same force that helps airplanes fly.

Just as the wind goes across the top of a curved wing of an airplane, making the pressure on the wing lower on top than underneath, helping to propel the plane upwards, the curved surface of the ping pong ball reduces the pressure around the sides of the ball and increases it on the top, the other side of where you were blowing.

This increased pressure on the top of the ball forces it back down into the funnel.

Not what you expected, huh?

What Else Can We Do with A Ping Pong Ball?

In an earlier post, When Is a Piece of Paper Like an Airplane Wing, when we talked about airplane wings and demonstrated Bernoulli’s principle with a piece of paper, we also described how you could float a ping pong ball with a hair dryer.

Let’s start with that, and add some more ideas. This experiment requires adult supervision because you will be using a knife.

You Will Need:

4 or 5 ping pong balls
A hair dryer
An empty, round, cardboard salt container
A toilet paper tube

Here’s What You Do:

Turn the hair dryer on maximum power, cool setting
Turn the hair dryer so the air is blowing up
Hold a ping pong ball in the air blowing up
Let go of the ball.

What Happens?

The ping pong ball will float. Bernoulli’s principle is at work again. The flowing air around the curved ball allows you to keep the ball in the air without touching it.

Next, cut off both ends of the salt container. The cardboard is stiff, so this requires adult supervision.

Now, float the ping pong ball in the air over the hair dryer and carefully slip the cylindrical salt container over the floating ball.

It will float just above the top of the cardboard container.

Any Other Tricks?

Now, float the ping pong ball in the air over the hair dryer and carefully slip the cardboard toilet paper tube over the ball.

The ball will shoot through the air like a rocket!

Now, try to float two balls in the air over the hair dryer. Three? Four?

I never got past two, but even this was fun as they kept dancing around each other in the air.

Thanks to the California Science Center for these activities and explanation of Bernoulli’s principle.

What would happen with a paper towel tube?

What would happen with a funnel big enough for the ping pong ball to fit through the small end?

What would happen with a square box instead of a cylinder?