Science Fenns K-5Grades K to 5
A child holding a flashlight to a globe tilted on a table, with the beam hitting the top half.

Science / All lessons / Seasons and the Moon

Why We Have Seasons

Tilt, not distance.

Lesson 23 of 40

Try this first

Before we start

Today’s story

Why We Have Seasons

Hold a flashlight straight at a wall. You see a bright, small circle. Tilt the flashlight. The light spreads out and looks dimmer.

Sunlight works like that. Earth is tilted. When your part of Earth leans toward the Sun, light hits more directly. Days are longer too. That is summer.

When your part leans away, light is spread thin. Days are shorter. That is winter. Distance does not decide it. The tilt does. Follow the steps.

See it

Five steps. Every time.

    Hands on

    Flashlight and Globe

    20 minutes · Do this with a grown-up nearby

    You need

    • Globe or ball
    • Flashlight
    • Dark room
    • Pencil and paper
    • Marker for a sticker

    Do this

    1. Put a sticker on the globe where Texas is.
    2. Dim the room.
    3. Tilt the globe so Texas leans toward the flashlight.
    4. Shine the light from the same distance.
    5. Draw how big and bright the light spot looks.
    6. Tilt the globe away and shine again.
    7. Compare the two drawings.
    Write or draw: Two drawings of the light spot, one for each tilt.

    Watch for: The light is spread over a bigger area when tilted away. That means less heat in each spot.

    Safety: Do not shine a flashlight in anyone's eyes.

    Same every time

    Three rules

    Rule 1The tilt makes the seasons.

    Distance from the Sun does not.

    Rule 2North and South are opposite.

    When Texas has summer, Australia has winter.

    Rule 3Models help, but they simplify.

    A globe is much smaller than Earth.

    Grandpa Fenn’s notebook

    Say it like a scientist

    axis
    The imaginary line Earth spins around.
    orbit
    The path one object takes around another.
    tilt
    A lean away from straight up.
    season
    A part of the year with its own weather and day length.

    Poppy’s quiz

    Six questions

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

    Talk about it

    Say it out loud

    • How do you know distance is not the cause of seasons?
    • How does your family notice the change of season in Texas?
    Did you know

    Mars is tilted about 25 degrees, close to Earth's tilt. So Mars has seasons too.

    Someone who does this

    An astronomer studies how Earth moves around the Sun.

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