This spinning spiral isn’t magic, it’s science! Learn how to do this experiment yourself — and the science behind it — below 👇

What you need:
Scissors
Sewing needle
Thread
Tealight
Lighter or matches
Paper

How to make a spinning spiral:
Take your paper and cut it in a spiral shape.
Cut a small hole in the center of the spiral.
Thread the thread through the hole. If you have trouble with this, use a needle to help.
Tie the thread in a knot at the underside of the spiral.
Light the tealight.
Hold the string and place the spiral above the tealight to watch it spin!

What’s going on?
When air is heated, it expands as its molecules spread out away from each other. In other words, hot air is less dense than cool air. This means that hot air will rise above cool air, and that's exactly what you're seeing with this spinning spiral! As the hot air rises, cooler air flows in to replace it - but then the cool air gets heated by the candle, and the whole thing repeats. This cycle of moving air is called a convection current.

The rising hot air makes the spiral spin because of its shape. Just like a pinwheel, the air gives the spiral a push in one direction and starts it spinning. In a frictionless world, the spiral would keep spinning forever (or, at least until the candle burned out)!

Special thanks to our host, Alex!

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