Contributor: Rebecca Highland. Lesson ID: 10345

How do satellites stay up there? Why doesn't the moon go flying out into space? See an astronaut drop a hammer and feather, watch cool videos, and do an experiment to learn about gravity and velocity!


Space Science and Astronomy

learning style
personality style
Grade Level
Intermediate (3-5)
Lesson Type
Quick Query

Lesson Plan - Get It!

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  • Have you ever wondered why the moon seems to change shape in the sky?

It's because the moon revolves around the earth, just like the earth revolves around the sun! This is called orbiting.

Watch this video to learn more.

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An orbit is a path that an object follows around another object.

All the planets orbit the sun, but some things orbit the earth, too!

Two big things orbit the earth: man-made satellites and its natural satellite, the moon. Think about how this is possible.

If you throw something (say, your pen) up into the air, it falls right back down because of gravity. Objects are attracted to the center of the earth.

  • So, why can the moon and satellites circle the earth without falling into it?

Two big factors keep satellites like the moon in orbit rather than crashing into the planet.

  1. The first is the gravitational pull of the earth. The earth is big — big enough that it has its own pull of gravity toward the center of the earth!

  1. The second factor is the velocity of the object. Velocity means speed in a certain direction. So, as long as the speed of an object's revolution is in balance with the earth's gravity, the object will stay in orbit.

Watch the video below to learn more.

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Watch the moon's orbit around the earth with this video showing one month scaled to just 10 minutes.

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Head to the Got It? section to explore the moon more.

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