Crush a bottle without even touching it and learn about air pressure at the same time!

Air Science Experiment:  The Amazing Bottle Crush

What you will need:

• A plastic bottle without a lid
• A coin, big enough to cover the mouth of the bottle
• A cup of water
• A freezer

What you will do:

1 Put the empty bottle into the freezer for 5 minutes.
2 Wet the coin in the cup.
3 Take the bottle out and stand it on a table. Lay the wet coin over the mouth of the bottle. You have to be quick!

What is going on?

We know that air has molecules. When we put the bottle into the freezer, the air molecules inside the bottle cooled down, and moved closer together. This made room for more air, so air from the freezer
moved into the bottle as well.

When we took the bottle out of the freezer, the air molecules warmed up, and started to spread out again. That meant there was no room for the extra air, so it had to go! The molecules of air pushed past the coin to get out.

Monster Challenges:

• How many coins can the air push? If you put 2 coins on top of the bottle, is it too heavy for the air to push past? 3? 4?
• What happens if you put a piece of paper over the mouth of the bottle instead of the coin?
• Can you explain why the coin needs to be wet?

Teaching Notes:  

 Topic: 

Air

 Key Concepts:

¨ Air has molecules.  Molecules get closer together when they are cool and further apart when they are warm.  Air pressure.

 Resources:

 Investigation Record IR01– one copy per student

• Experiment Description Air A04– one copy per student
• Empty plastic container with lid, hot water

 Lesson Notes:

This lesson is suitable for younger students as a demonstration – safety with the hot water is the issue.

With older students, group them into small groups with responsible students given the job of filling the bottle.  Hot tap water is sufficient for the experiment, but in the interest of safety remind everyone of the dangers – even tap water can burn.

Remind students to listen carefully to instructions, and to OBSERVE their experiment.

As a class discuss the experiment prior to undertaking it, and students should complete the sections of their Investigation Report IR01 from ”Title to “Hypothesis”.

 What should happen in this experiment, and why?

After the hot water is swirled and poured out and the lid is put on the bottle, the bottle should collapse.  This may take a few minutes.

Follow up discussion questions:

• What would happen if we didn’t put the lid on the bottle tight enough?
• What do you think would happen if we put the lid on the bottle then put the bottle in the freezer?

Get this experiment here or as part of a bundle of Air Experiments here.