Although years of movies and TV shows have planted the idea in our head that quicksand is some sort of gritty soup that will swallow you whole in seconds, it’s actually a lot more solid than you’d probably think (and you’d float in it). There is one way, though, to get sand to act just like a fluid, and it’s both simple and mesmerizing to watch.

This GIF made the rounds on Reddit today, and it shows sand that is completely dry and yet moves and behaves almost as water. Check it out:

What the heck is going on here? Well, it turns out that this is called a fluidized bed, and the Royal Institution video below demonstrates and explains the concept:

You can make a fluidized bed by blowing air through the bottom of a container of sand. Doing so increases the space between the sand particles, allowing them to move among each other more freely. By reducing internal friction in the sand, the grains are free to swim around as particles in a liquid do.

Seeing the sand move like a liquid is wild enough, but the most fascinating part is when the presenter in the above video drops objects into the sand and they splash and bob, making waves as if you had just thrown them into your bath tub.

Featured image: The Royal Institution

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