# A Ping Pong Predicament

Contributor: Kaitlyn Zimmerman. Lesson ID: 12811

Oh no! You're having a wild game of ping pong and suddenly the ball gets a dent in it! Where will you find a tiny person with a hammer to get inside and hammer it out? Quick! We need a glass of water!

categories

## Physics

subject
Science
learning style
Visual
personality style
Golden Retriever
Primary (K-2), Intermediate (3-5)
Lesson Type
Quick Query

## Lesson Plan - Get It!

Audio:

Ben and John are having a ping pong tournament and it has gotten intense! They have already cracked two ping pong balls and only have one dented ball left!

They won’t be able to finish their match unless they fix their last ping pong ball — but they cannot seem to do it! Little do they know, the amazing properties of air can easily fix their problem!

So far in this series about Air, you have learned how air is all around you and can fill any space it finds!

(If you missed the previous lesson in our Air series, find it in the Related Lessons in the right-hand sidebar.)

We say that air has an indefinite shape and indefinite volume.

• What does that mean?

You know what shape means. Everything that's solid has a shape: like a ball, a person, or a sugar cube.

Liquids don't have a definite shape. They take on the shape of whatever container they're in. Think of water being poured from one container to another.

Air is a gas, and like all gases, doesn't have a definite shape either.

Volume is the amount of space that an object occupies.

A liquid takes up the same amount of space no matter what container it's in. If you have a cup of water and pour it in a different container, it will still be one cup of water.

Air takes up space, but the space it fills is not definite. It fills all empty spaces it can reach.

Let's take a closer look at the concepts of shape and volume in the slides below:

• Did you know that if you change the temperature of air, it affects how much space the air takes up?

When putting this property of air to use, you can remove the dent of a ping pong ball, too! Let's tune in to Flo to find out how!

As you saw in the video, air is made up of molecules — small units of air — that react to temperature changes.

Just think:

When the temperature changes, it affects the amount of air that can fit into a given space.

When air is heated, air molecules move faster than they do when they are cool.

Since the ping pong ball was placed into a cup of warm water, the air inside the ball was heated and expanded! This is an example of the heated molecules moving faster and faster inside the ping pong ball until enough pressure was generated to pop out the dent!

This may just be the answer to help John and Ben get back to their ping-pong game!

In the meantime, continue on to the Got It? section to test your memory!

Interactive Video