Last updated at 12:05

How do you play ping-pong in space?

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Astronaut Scott Kelly has celebrated his 300th day in space with the invention of a new sport - water ping-pong.

That's ping pong where the actual ball is made of water.

Whereas water on earth is pulled down by gravity so it spreads out and fills whatever container it's in, water in space floats in mid-air in the shape of a ball.

Scott used special paddles that repel water to bounce the water droplet back and fourth.

Looks like fun!