Science Fenns K-5Grades K to 5
A row of eight Moon shapes across a dark blue Texas sky above a barn.

Science / All lessons / Seasons and the Moon

Moon Phases

Watch the Moon for a month and predict the next phase.

Lesson 24 of 40

Try this first

Before we start

Today’s story

Moon Phases

Look up some night. The Moon may be a thin curve. A week later it looks like a half circle. Later it is a bright circle.

The Moon does not change shape. It always has one half lit by the Sun. As the Moon travels around Earth, we see more or less of the lit half. At a new Moon the lit half faces away from us.

The pattern repeats about every 29 days. That means you can predict it. Follow the steps.

See it

Five steps. Every time.

    Hands on

    Moon Diary

    A few minutes each night for a month · Do this with a grown-up nearby

    You need

    • Notebook
    • Pencil
    • Calendar
    • Moon chart from an almanac

    Do this

    1. Draw a circle for each night on a calendar page.
    2. Go outside at the same time each evening.
    3. Shade the dark part of the Moon you see.
    4. Write the date next to each drawing.
    5. If it is cloudy, write cloudy.
    6. After one week, predict the shape one week later.
    7. Check your prediction.
    Write or draw: A set of Moon drawings with dates and a prediction.

    Watch for: The shapes change a little each night. The lit part grows, then shrinks.

    Safety: Go out with an adult in the evening.

    Same every time

    Three rules

    Rule 1Record the date.

    A pattern needs dates to count days.

    Rule 2Look from the same place.

    It makes your drawings easier to compare.

    Rule 3Check cloudy nights.

    Skip a night and say so. Do not guess.

    Grandpa Fenn’s notebook

    Say it like a scientist

    phase
    A shape of the Moon that we see.
    waxing
    Getting bigger from one night to the next.
    waning
    Getting smaller from one night to the next.
    crescent
    A thin curved sliver.

    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 the Moon does not make its own light?
    • Have you seen a full Moon over a Texas field? What did it look like?
    Did you know

    The Moon always shows the same face to Earth.

    Someone who does this

    A ship pilot uses the Moon's pattern to know when the tides run high.

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