Science Fenns K-5Grades K to 5
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The Water Cycle

The Sun powers it.

Lesson 25 of 40

Try this first

Before we start

Today’s story

The Water Cycle

Hang wet laundry on a Texas summer day. It dries fast. The water did not vanish. It went into the air as vapor.

High up, the air is cold. The vapor cools and turns back into tiny drops. Those drops make clouds. When the drops grow heavy, they fall as rain, snow or hail.

The rain runs into creeks and soaks into soil. Then the Sun lifts it again. Round and round. The Sun is the engine. Follow the steps.

See it

Five steps. Every time.

    Hands on

    Water Cycle in a Bag

    20 minutes plus a day of watching · Do this with a grown-up nearby

    You need

    • Poppy bag
    • Water
    • Blue food coloring
    • Tape
    • Sunny window
    • Marker

    Do this

    1. Put a small amount of water and a drop of coloring in the bag.
    2. Seal it tight.
    3. Tape it to a sunny window.
    4. Draw a line where the water level begins.
    5. Check the bag after an hour and again later.
    6. Look for drops on the upper part of the bag.
    7. Draw what you see.
    Write or draw: A drawing of the bag with arrows for evaporation, condensation and collection.

    Watch for: Drops form near the top where it is cooler. Then they run back down.

    Safety: Do not open the bag after it is sealed and do not drink the water.

    Same every time

    Three rules

    Rule 1The Sun powers the cycle.

    Without its heat, water would not rise.

    Rule 2Water changes form.

    It is the same water in solid, liquid or gas.

    Rule 3The cycle never really stops.

    It is happening right now.

    Grandpa Fenn’s notebook

    Say it like a scientist

    evaporation
    Liquid water turning into water vapor.
    condensation
    Water vapor turning into tiny drops.
    precipitation
    Water falling from clouds.
    vapor
    Water as an invisible gas.

    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 water in a puddle goes into the air?
    • Where does the rain on your family's land or street end up?
    Did you know

    Water on Earth is very old, and the same water has been cycling for billions of years.

    Someone who does this

    A hydrologist studies where water goes and how much there is.

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