Shrinking Air: Hot vs. Cold

Contributor: Kaitlyn Zimmerman. Lesson ID: 12813

Did you know that hot and cold air are always in a constant battle? No matter what, they are always bumping into each other. Did you know that you could use air to shrink objects? Try it out yourself!


Physics, Physics

learning style
personality style
Golden Retriever
Grade Level
Primary (K-2)
Lesson Type
Quick Query

Lesson Plan - Get It!

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Chloe LOVES ballet. She plans to spend all day practicing for her upcoming performance.

When Chloe gets to the studio, she is hit by a wall of cold air as she walks in the door. After an hour of practicing, Chloe is so cold that she wants to go home. She feels too cold to move!

  • Have you ever been so cold, like Chloe, that you've been too cold even to move?
  • Have you ever played outside on a cold, snowy day for so long that you only wanted to curl up to stay warm?

If so, then you and molecules have a lot in common!

Just like Chloe, air molecules can become cold too!

They may not shiver or say they are cold, but you can see how they react when they are cooled.

  • What do you think will happen to air molecules when cooled?
  • Do they speed up and move around faster, or do they slow down and move around at a slower pace?

You know warm air can take a dent right out of a ping-pong ball.

  • What do you suppose might happen when something comes in contact with cold air?

Tune in to Flo to see just how it works!

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  • Did you see how the sides of the bottle bent in?

This happened because the air molecules, when cooled, pulled in closer together, taking up less space inside the bottle.

As this happened, the bottle also pulled in because the air pressure of the warmer air on the outside was greater than that of the cold air inside the bottle.

Once that all makes sense, move to the Got It? section for a quick quiz!

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