Science Fenns K-5Grades K to 5
A child on a Texas porch at dusk looking up at a bright Moon with the last of the sunset behind the pecan trees.

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Sun, Earth and Moon Orbits

Earth circles the Sun. The Moon circles Earth.

Lesson 23 of 41

Try this first

Before we start

Today’s story

Sun, Earth and Moon Orbits

Stand in a pasture at sunset. The Sun slides down behind the mesquite trees. It looks like the Sun is moving. It is not. You are the one moving.

Earth is a giant ball, and it travels in a big loop around the Sun. That loop is an orbit. One full orbit takes about 365 days. We call that a year.

The Moon has an orbit too. It circles Earth, not the Sun. One trip takes about a month. Let's walk through the steps.

See it

Five steps. Every time.

    Hands on

    Walking Orbits

    25 minutes · Do this with a grown-up nearby

    You need

    • A big open space like a yard or gym
    • Three people
    • A yellow hat for the Sun
    • A blue paper for Earth
    • A white paper for the Moon
    • A timer

    Do this

    1. Pick one person to be the Sun. Have them stand still in the middle.
    2. Let a second person hold the blue paper. This is Earth.
    3. Walk Earth in a wide circle around the Sun.
    4. Let a third person hold the white paper. This is the Moon.
    5. Have the Moon walk in a small circle around Earth while Earth keeps walking.
    6. Time how long one lap takes for Earth. Swap jobs and try again.
    Write or draw: Draw the path of Earth and the path of the Moon. Label the Sun, Earth and Moon.

    Watch for: Notice that the Moon has to keep up with Earth. Notice that the Moon makes a smaller loop than Earth.

    Safety: Walk slowly and keep your eyes up so nobody bumps into anyone.

    Same every time

    Three rules

    Rule 1The Sun is the center.

    Earth and the other planets circle it.

    Rule 2Earth spins and orbits.

    These are two different motions.

    Rule 3The Moon circles Earth.

    It does not circle the Sun by itself.

    Grandpa Fenn’s notebook

    Say it like a scientist

    orbit
    The curved path an object takes around another object.
    Earth
    The planet we live on. It circles the Sun.
    Moon
    The big rock that circles Earth.
    year
    About 365 days. The time Earth takes to orbit the Sun once.

    Poppy’s quiz

    Six questions

    Tap an answer. Green means right. You will see why.

    Talk about it

    Say it out loud

    • Why does the Sun look like it moves across the sky? How do you know it is really us moving?
    • Where is a good spot near your home to watch the Moon rise?
    Did you know

    Earth moves around the Sun at a speed of many thousands of miles every hour, and we do not feel a thing.

    Someone who does this

    An astronomer studies the Sun, Earth, Moon and the stars.

    BeforeEnergy DetectiveNext lessonModel the Orbits