{"id":66228,"date":"2026-08-06T05:13:42","date_gmt":"2026-08-05T20:13:42","guid":{"rendered":"https:\/\/phys-edu.net\/wp\/?p=66228"},"modified":"2026-08-06T05:13:42","modified_gmt":"2026-08-05T20:13:42","slug":"why-doesnt-a-spinning-disk-fall-over-discover-the-gyroscopic-effect-with-a-hand-spinner-and-a-cd","status":"publish","type":"post","link":"https:\/\/phys-edu.net\/wp\/?p=66228&lang=en","title":{"rendered":"Why Doesn’t a Spinning Disk Fall Over? Discover the Gyroscopic Effect with a Hand Spinner and a CD!"},"content":{"rendered":"

I’m Ken Kuwako, the Science Trainer. Every day is an experiment.<\/strong><\/span><\/p>\n

I found this cute yellow hand spinner at Daiso. Hand spinners are also sold at 100-yen shops like Seria, and although they’re inexpensive, they spin surprisingly well.<\/p>\n

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At first glance, it looks like nothing more than a fun little toy. But glue it to the center of an old CD, and it instantly transforms into a fascinating physics demonstration that lets you experience one of the most surprising effects in mechanics firsthand.<\/p>\n

Here’s what the front looks like.<\/p>\n

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And here’s the back.<\/p>\n

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I came across this idea on the NGK Science Site and decided to build one myself. It turned out to be even more entertaining than I expected, so I had to share it. The theme is the “gyroscopic effect”\u2014the same mysterious phenomenon that keeps spinning tops upright and bicycles stable while moving.<\/p>\n

A stationary CD falls over immediately<\/h3>\n

Let’s start with the simplest test.<\/p>\n

Without spinning the hand spinner, try standing the CD upright on a desk.<\/p>\n

As expected, it tips over almost instantly.<\/p>\n

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It’s a good reminder of just how unstable a thin disk is when you try to balance it vertically.<\/p>\n

Spin it first… and something amazing happens<\/h3>\n

Now comes the fun part.<\/p>\n

Give the hand spinner a good spin, then place the CD upright in exactly the same way.<\/p>\n

The result is remarkable. Take a look at the video.<\/p>\n