How to Make a Whirring and Whirling Balloon Experiment
Watch a coin whirl around inside a balloon and listen to the noise it makes then learn about how it all works.
What you need:
A small coin
A balloon (preferably one that is easy to see through)
What to do:
Insert the coin into the balloon.
Blow up your balloon to a size that you can easily hold in one hand and then tie it off.
Hold the smallest end of the balloon in one hand with your palm facing down and swirl the balloon in little circles. You want the coin to spin around the inside of the balloon.
When you feel you have got the coin spinning at a good speed stop spinning the balloon.
Watch how long the coin keeps spinning for and try it again to master the technique.
Why does the coin keep spinning for so long?
You start it spinning so the energy you put into this helps to keep it spinning. The shape of the balloon guides the coin to go around in circles rather than straight.
Centripetal Force is the force that helps to keep the coin moving around in a circle even when gravity and friction are trying to slow and pull it down.
Centripetal is Latin for ‘Center Seeking’ because it pulls the object towards it helping it to keep moving around.
Other examples of Centripetal Force:
• Swinging a Poi around in circles
• A loop in a roller coaster
• Planets orbiting around the sun
Whirring Balloon
Try this experiment with a nut (the metal kind) or a coin with rough edges, it will make a whirring or screaming noise as it spins. This is because the rough edges cause it to bounce along inside the balloon making vibrations against the balloon’s surface that is transferred out as sound.