NOVA Online | Stationed in the Stars | Free-falling and weightlessness

The Point
When you are in a free fall, you feel as though you are weightless.

Maybe you've never been skydiving, but you probably have an idea of what it might be like from watching movies and television. If it wasn't for the air rushing by, the skydiver would seem to be floating. The skydiver would really feel as though he was floating if he began his dive high enough, where the atmosphere is thin. This is exactly what happened to Joe Kittinger when he leapt from his balloon at 100,000 ft. (See the NOVA Hot Science Skydive from the Stratosphere.) Immediately after stepping out of the gondola, Kittinger thought he was floating... that is, until he looked up and saw that he was quickly moving away from his balloon.

Falling elevator animation

Still not convinced that free-falling makes you feel as though you're weightless? Then imagine you're in an elevator that's at the top of a high building. The elevator's cable is cut and there's no safety brake. Both you and the elevator are now accelerating at the same rate. If you press your toes down on the elevator's floor, what do you think happens? The answer is that you float up. Of course, you're not really floating up. You're just falling down slightly slower than the elevator, but to you it seems as though you're floating.

The Point (again): When you are in a free fall, you feel as though you are weightless.

Next: Part 2...

Photo: Peter D. Sundberg/Corbis

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