Friday 3 May 2013

Science: Kissing Balloons!

Yesterday, we had great fun with this experiment.  Today we've been looking into the science of it so here it is shared.  Really it's better if the two balloons gently touch but you get the idea.  The most important thing about these experiments is to have fun when doing them after all.  If you would like to have a go this is how to setup your kissing balloons experiment...

What you will need:
  • 2 balloons
  • string
  • a ruler
  • a broomstick or long pole
  • scissors (for cutting string)
  • A person to blow air
How to do the experiment... 

Blow up two balloons.

Attach a piece of sting to each balloon.
We balanced a broom stick (you could use any other long pole) across the back of two chairs.

Ensure that the two balloons are 6 inches apart.

Make sure the balloons are at nose height.

Gently blow between the balloons.  Not at the balloons though.  Try blowing a little harder if it doesn't work at first until you have the result you are looking for.

What happened?

The balloons touched as if they were kissing!  When you blow between the balloons, like magic, they get closer together until they touch. 


Because when you blow in between the balloons you lower the air pressure between them - try to imagine the air molecules as little balls and when you blow through the balloons you blow them away. This means that the air pressure around the other side of the balloons is then higher. Higher air pressure always pushes and this is what pushes the balloons together.

Here a couple of diagrams to help you see what happened...

In the first diagram we can see all the air molecules are the same amount all around the balloons.

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