Science Smarts: Monster balloons

By Patty Rooks on September 20, 2025.

I know it is early, BUT I see Halloween things everywhere when I am out. Of course, this has me thinking about some science we can do in the weeks or days leading up to this frightful day!

Halloween science has endless possibilities, but I only have so much room each week – I promise to narrow it down to my favourites only to share with you in the coming weeks. They will be simple, fun and frightful for you at home, in the classroom or that party you might throw. Let’s get started!

*Remember to ask an adult before doing this experiment.

– Balloons (good quality 9″ to 11″ in size work well)

– 1/4″ hex nuts

Procedure

1. Place one of the hex nuts inside the balloon and blow the balloon up. Be careful not to blow the balloon up too much as it will pop easily. Tie up the balloon.

2. Hold the balloon in your palm and swirl in a circular motion. Keep swirling, past the point of the hex nut bouncing around then begins to roll around the inside of the balloon.

3. Listen. What is that sound? Does the balloon have a monster in it?

What is going on?

This is one of my favourite SOUND experiments. You can make those earie spooky Halloween sounds easily. You are creating a moaning sound because the nut is circling the inside of the balloon creating centripetal force. Centripetal force is the inward force on a body that causes it to move in a circular path. The sound is created by the uneven sides of the hex nut vibrating against the inside wall of the balloon.

To prove that this is in fact what is happening try replacing the hex nut with a penny. The penny may spin easier in the balloon the sound is gone. Experiment with different sizes of hex nuts and or coins.

DO not forget to add this to your Spooky Halloween Party ideas!

Teachers, do not forget to book your hands on Learning Kits for the school year. New to our resources this year includes the Spike Lego specifically for grades 6-8. Book now as slots are filling up fast! As well, a number of kits have been realigned with the NEW Alberta Science Curriculum over the summer. Email Patty for details and topics.

Patty Rooks, senior scientific consultant Praxis Science Outreach Society. Praxis has moved! We are very fortunate to be located in the Community Futures Entre Corp Building at #202 556 Fourth St. SE, Medicine Hat, Alberta, T1A 0K8. For all your science needs, please email praxis@praxismh.ca.

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