Inside the International Space Station (ISS), you can see astronauts floating about.

Do you think gravity disappears in space? Well, not exactly.

Then, why can they float?
 

Actually, a strong force of gravity, about 90 percent of the gravity on Earth, is placed on the ISS. But it still looks like things are floating. The ISS itself looks like it's floating in space. What a mystery!

The secret is in the motion of the ISS. How can the ISS stay floating in space?

Let's start with a little brain exercise. Think about throwing a ball.
 

If you throw a ball on Earth, it will fly for a little bit, and then fall to the ground.

If you throw the ball faster, it will fly a little bit further.

So, if you throw a ball much faster - much much faster - and much much much faster.

Could the ball eventually go all the way around the earth, if you keep throwing the ball faster and faster?