Riddle: Try to correctly answer all 3 questions below.

1. A mom buys a boy a helium balloon at the zoo on a wind free day. The boy is scared when he sees a big tiger and accidentally lets go of the balloon. What will happen to the balloon?
a. It will rise
b. It will remain suspended at the same height he let it go
c. It will fall to the surface

2. An astronaut on the moon fills a balloon with helium. He then walks on the moon's surface holding the balloon in his hand. He then lets go of the balloon. What happens to the balloon?
a. It rises
b. It falls to the moon's surface
c. It remains suspended at the same height he let it go

3. The space shuttle is in orbit around the earth. An astronaut fills up a balloon with helium inside the space shuttle. The astronaut then holds the balloon in her hand. What happens when the astronaut lets go of the balloon? Assume a zero gravity environment.
a. It rises to the roof of the space shuttle
b. It falls to the floor of the space shuttle
c. It remains suspended at the same height the astronaut let it go

Answer to Riddles: On Earth, the Helium inside the balloon is less dense than the air around it. The balloon will rise once the boy at the zoo lets it go. Since the balloon and the air around it are under the influence of gravity, the less dense air will want to rise within the more dense air (Answer A).

On the moon there is no atmosphere. There is still gravity although it is much less than Earth gravity. Having no atmosphere is equivalent to being in a vacuum. Although Helium is a light gas it will be more dense than having no air at all. On the moon the Helium balloon under the influence of gravity will fall to the moon's surface (Answer B).

In the space shuttle the shuttle is falling toward the Earth at the same time it has enough forward speed to always go around the Earth as it tries to fall towards it. In other words the shuttle is in an orbit around the Earth. In this environment gravity will not be sensed since the shuttle and the astronauts are falling together at the same rate. Assuming that perfect zero gravity is achieved then the balloon and any other object no matter how light or dense will remain at the same height they are let go (Answer C).