How do you turn a ping pong ball into a nitrogen-powered whirling dervish? Just get some liquid nitrogen and let the atmosphere do the work for you.
A few hours ago I tweeted out an awesome GIF of a Imgur user dipping a ping pong ball into liquid nitrogen — nitrogen gas cooled down below −195.79 °C (−320 °F) — and setting it down on a surface. The ball then begins to spin at amazing speeds while a cloud of nitrogen gas pours out of it. YouTuber TheBackyardScientist saw the post too, and had to try it immediately. Armed with a high-speed camera and some liquid propane, he replicated the results and got a read on the speed.
Liquid propane, like liquid nitrogen, boils at incredibly low temperatures — both would boil in the dead of an arctic winter. So when the propane is removed from its container and placed into the ping pong ball, the liquid boils and expands into a gas almost immediately. Poke a small hole in the side of the ball and this expanding gas jets out, turning it into a tiny rocket. As the Backyard Scientist found out, there’s enough escaping mass to get the ball spinning at almost 30,000 revolutions per minute. You can turn a ping pong ball into a tiny pulsar at those speeds!
And the best part is that this is a little science demo you can do yourself if you’re careful. All you need is a ping pong ball, some liquid nitrogen, and a pin.