Blowing up balloons with air pressure

No need to huff and puff to blow balloons up; let an empty bottle do it for you!

What you’ll need:

– A hard plastic bottle

– A balloon

– Scissors


1. Cut a small hole 1cm in diameter on the side of the bottle using your scissors.

2. Stuff the balloon into the bottle stretching the balloon opening over the mouth of the bottle.

3. Notice how you can’t blow up the balloon when your finger is over the hole.

4. Put your mouth over the hole and suck the air in the bottle out … see what happens! You actually blow the balloon up by sucking the air in the bottle out!

What’s the science?

Putting a hole in the bottle allows the air pressure inside to be released and the balloon to inflate. Blocking the hole traps all the air inside and stops the air pressure from escaping.

Adult supervision advised.

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