Raven and Rocket sit on the beach, watching the waves creep up the sand. Hours later, the water has moved far out.
"The ocean ran away," Rocket jokes.
Raven points at the pale Moon in the afternoon sky. "What do you notice up there?" she asks.
Nova draws a faint line from the Moon to the sea. "The Moon pulls too," she says. "Would you like a hint about the tides?"
Rocket sits up. "Gravity is not just for falling apples," he says.
Earth's gravity keeps you on the ground and makes dropped things fall.
The Moon's gravity pulls on Earth's oceans. It pulls the seas toward the Moon, which causes the ocean tides.
Earth and the Moon both have gravity that pulls objects toward their centers.
| What we see | Which gravity is at work? |
|---|---|
| A dropped ball falls to the floor | Earth's gravity |
| Ocean tides rise and fall | The Moon's gravity |
| Astronauts bounce on the Moon | The Moon's weaker gravity |
Earth's gravity holds the oceans on our planet.
The Moon's gravity tugs on the oceans too.
That tug pulls the seas toward the Moon and causes the tides.
| Statement | True or false? |
|---|---|
| The Moon's gravity pulls on Earth's oceans. | ? |
| Gravity only works on falling apples. | ? |
| Earth's gravity makes dropped things fall. | ? |
You found gravity from your desk to the ocean. Tomorrow is Launch Lab with your family.