Book 2, Question 135 · Video
Why Is Earth Round?
Earth looks flat when you stand on it, but it is really a giant ball. Gravity pulled it into a ball! Gravity pulls every bit of a big planet toward the center.
Read the full answer →What Crafty Clover says in this video
Intro
Hey there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why is earth round?
The Big Idea
Earth looks flat when you stand on it, but it is really a giant ball. Gravity pulled it into a ball! Gravity pulls every bit of a big planet toward the center. A ball is the shape that wins. That is why big planets and moons are round, and tiny rocks can be lumpy.
Gravity Pulls Inward
Step one: gravity pulls inward. Every bit of rock, dust, and material feels a pull toward the center of the planet. When Earth was forming, that pull gathered material together.
Bumps Get Pulled Down
Step two: bumps get pulled down. High spots and bumps are pulled inward, and flatten over time. Small bumps like mountains are tiny compared with the whole planet. Nothing is pushing the ball into shape. Gravity does all the work.
A Ball Forms
Step three: a ball forms. The shape keeps changing until every point is about the same distance from the center. That shape is a ball, also called a sphere.
A Closer Look
Let's take a closer look at Earth's shape! First, gravity pulls inward. Second, bumps get pulled down. Third, a ball forms. And fourth, Earth spins, so it is a slightly squashed ball, with a tiny bulge at the equator.
Quick Facts
Quick facts! We do not fall off the bottom, because gravity pulls toward the center. So wherever you stand, down means toward the center of Earth. Earth's bulge at the equator is only about 21 kilometers, tiny compared with the whole planet. Big moons and planets are round, too, for the same reason.
Think Like a Scientist
Now, think like a scientist! With a grown-up, spin a ball that has a few drops of water on it. Watch where the drops go. Notice which drops stay on, and which fly off. Can you explain how this is like Earth's spin?
Outro
Earth is round because gravity pulls everything toward the center! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!