Strange physics trick lets people create a cloud in their own mouth

Effect shows how the sky’s clouds come about

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A simple, odd process allows anyone to create a tiny cloud in their own mouth.

The trick — which involves a bizarre but easy process — creates a cloud in your mouth that is exactly the same as those that are formed in the air. It is detailed in a new video by YouTube star Physics Girl, who runs a channel showing strange and fun parts of physics.

To make the cloud, you click your tongue repeatedly on the top of your mouth, making sure your mouth is closed and full of air. Then after 30 seconds, hold your mouth closed and blow out to pressurise it.

Then, the clouds should have formed. If you open your mouth and blow out, they should appear.

The clicking creates little water droplets, which makes them more able to evaporate. Then pressurising the mouth helps them to evaporate even more, because the pressure pushes the temperature up.

When blowing out, the temperature drops. Since the outside air is colder, the droplets cool and turn to water — becoming a cloud.

That is the same process that happens to make real clouds, in the sky. Big clouds are little droplets, which evaporate, head up into the sky, and then condense when they get up there.