[Live] Why Are Spinning Things So Powerful? Ken Kuwako’s Spin Science Show (Chiba City Science Festa 2026 Special Stage)
I’m Ken Kuwako, your Science Trainer. Every day is an experiment!
Have you ever noticed that a bicycle keeps rolling straight even when you let go of the handlebars? Strangely enough, those little spinning wheels have a deep connection to the way rockets hold their position in space. They look like completely different machines, but the secret behind both is “rotation.” This fall, I had the chance to take the stage at the “Chiba City Science Festa 2026” Special Stage, held at the Chiba City Science Museum, with a science show all about the mysterious power of spinning. I was the opening act on the first day, October 10, from 12:45 to 13:30.
The secret to why bicycles stay upright and rockets keep their heading is “rotation”! Why are spinning things so strong? Science Trainer Ken Kuwako unlocks the mystery with gyro airplanes and a thrilling air cannon demonstration.
Bikes That Don’t Tip Over, Rockets That Hold Their Course: What Do They Have in Common?
The venue had set up 80 seats, but the room was packed, with a few people standing at the back. (I heard afterward that 136 people had come to watch!) I started with a science show favorite, the air cannon, but this time we looked at it through the lens of rotation.
The ring of air that shoots out of an air cannon isn’t just flying straight ahead. It’s a doughnut-shaped chunk of air that keeps spinning, rolling from the inside of the ring out to the edge and back around as it travels. This is called a vortex ring. Because it’s spinning, it holds its shape and can travel a surprisingly long way. When I told the audience that the air ring was rotating, the kids leaned in and studied it very carefully.
Why Is a Spinning Object So Hard to Tip?
Next, we explored the wonders of rotation with X-Gyros and other props.
An object spinning at high speed tends to keep its axis pointing in the same direction. This is known as the “gyro effect.” It’s why a spinning top can stand upright without falling over. The same principle is used in the devices that control the orientation of satellites and rockets. A spinning object almost seems to follow a different set of physical rules from one that’s sitting still.
The Secret Behind the Returning Boomerang: Precession
In the second half of the show, I showed the kids how to make a boomerang and explained in detail why it comes back. Explaining precession in a way that elementary school students could follow was seriously tough!
Precession is what happens when you push on a spinning object: instead of moving in the direction you pushed, it reacts at a slight angle to it. A boomerang flies while spinning, so its upper wing moves through the air faster than the lower one and feels a bigger force. As a result, the boomerang’s axis of rotation gradually tilts, and its flight path curves into a circle that brings it back to you. A boomerang returning to your hand is like a little cosmic story, written by spin and air.
The Science Club Students Stole the Show, Too
This time, I brought along members of the Science Club from the Junior High School Attached to the Faculty of Education, Chiba University, to be my assistants and help liven up the stage. Ten minutes before the opening, the club ran its own mini stage show, the “Color-Changing Liquid Show.”
For the last ten minutes of my slot, the students put on another show, the “Limonene Balloon Show.” Limonene is a compound found in the peel of mandarin oranges and other citrus fruits, and it dissolves rubber, so any balloon it touches goes POP! Who knew that a piece of fruit peel could pack such a punch? Watching the students explain science in their own words made me proud. They looked so confident up there.
And That’s Not All: A Day Packed with Science
The stage lineup at this year’s Science Festa is wonderfully varied. There’s the “Theremin Laboratory,” where sound and science come together, and “Dr. Nadarenger,” famous for his big, bold experiments.
On the 11th, the festival also features a food-themed rap live show by “DJ Miso Soup and MC Rice.” Science, music, and food all mixed together? What a deliciously greedy two days!
Everyone is welcome to join in, and the planetarium is even free! For details, please visit the official website.
Photos from the festival also appeared in the Chiba Nippo newspaper.
“Easy, Fun Science for Everyone: Booths and Shows at the Festa Through the 11th, Held at Chiba City’s Kibo-ru”
https://www.chibanippo.co.jp/articles/1677835https://www.chibanippo.co.jp/articles/1677835
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Let’s bring the wonder and fun of science closer to home! This blog collects easy science experiments you can do at home, along with tips for making them work. Try searching around and see what you find!
・The content of Kagaku no Neta-cho (Science Idea Notebook) has been published as a book! Details here.
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