The Law of Inertia for Under $10: The Toy Air Hockey Puck That Eliminates Friction
I’m Ken Kuwako, your Science Trainer. Every day is an experiment.
The God of Science often smiles upon us in unexpected moments of daily life. Take a look at this video. The movement here clearly illustrates the Law of Inertia—that “an object in motion stays in motion unless acted upon by an external force.” The fact that this motion can be easily demonstrated by a toy costing less than 1,000 yen (about $10 USD) is truly amazing.
The “Scientific Gem” I Found at a Family Restaurant
The other day, I was at a family restaurant with my family. Near the register, there were all sorts of toys designed to catch children’s eyes. My two-year-old was captivated by the Thomas the Tank Engine toys. While standing next to my child, I was looking around myself… and suddenly, one particular box caught my attention. It was an Air Hockey Toy (Nokonoko Air Hockey).
Maybe it’s an occupational hazard, but I had an instant thought: “I bet I could use this in class!” I quietly bought it, trying not to let my wife notice. Back at home, I opened the box with great anticipation…
Inside, there were simply an air hockey puck (disk) and the mallet (paddle) to hit it with.
Why Does It Move So Smoothly?
The video at the beginning shows what happened when I immediately played with it.
As you saw in the video, the puck glides across the table much more smoothly than expected—almost as if it were on ice. This is quite mysterious, isn’t it? Normally, when you slide an object across a surface, frictional force acts between the object and the floor, causing it to stop quickly. But this toy is different.
The secret lies on the bottom of the puck. A motor built into the top spins a fan, pushing air out downwards. This air creates a layer between the puck and the table, making the puck float slightly and reducing friction to the absolute minimum. It’s the exact same principle as a hovercraft, the amphibious vehicle! The motor sound is a bit loud, like a vacuum cleaner, but the effect is incredible.
The Savior That Solves Classroom Problems
In fact, I previously used a similar mechanism built by hand in my classes. However, handmade items inevitably had durability issues, and they would often break when students enthusiastically handled them. Also, until now, to demonstrate “Uniform Linear Motion,” we had to specifically buy dry ice for the experiment.
While dry ice is difficult to prepare and store, this toy only requires two AAA batteries and can be used anytime. The durability is no longer a concern, and since it’s so inexpensive, it’s easy on the budget to purchase enough for every group in the class. I believe I have found the perfect teaching material for introducing the Law of Inertia to students.
The excitement of science isn’t reserved only for expensive lab equipment. I encourage everyone to look for seeds of science in your everyday surroundings. I highly recommend this!
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