Book 2, Question 136
Why Do Things Fall Down?
When you drop a ball, it always falls to the ground. Have you ever wondered why? Gravity is a pull toward Earth! The moon has gravity too, just weaker.
More fun facts
- Earth's gravity holds down our atmosphere and the air we breathe.
- On the Moon, astronaut David Scott of Apollo 15 dropped a hammer and a feather at the same time, and they hit the ground together.
- There is almost no air on the Moon, so nothing slowed the feather down.
- Hundreds of years earlier, Galileo concluded that all objects dropped together fall at the same rate.
- Galileo rolled balls down ramps and saw them speed up as they rolled.
- Something moving only because of gravity is said to be in free fall.
Sources: NASA Space Place, NASA Science, NASA, NASA
Questions kids ask
Why does a feather fall slower than a ball on Earth?
Air pushes back on falling things with a force called drag. A light, fluffy feather gets slowed down by the air much more than a ball.