Science Fenns K-5Grades K to 5
A Texas prairie with a tall storm cloud building on the horizon and a farmer looking up from a fence line.

Science / All lessons / Water, Rock and Landforms

How Weather Forms

The water cycle drives the weather.

Lesson 27 of 41

Try this first

Before we start

Today’s story

How Weather Forms

A hot July afternoon in North Texas. The air feels sticky. By evening a tall cloud has built up, and a storm rolls in. What happened in between?

The Sun heated the ground and the water. Water evaporated and the air filled with water vapor. Warm air is lighter, so it rose. High up it cooled and the vapor condensed into drops. Those drops made clouds.

Weather is what the air is doing right now. Temperature, wind, clouds and rain all come from the water cycle and the Sun's heat. The steps show how.

See it

Five steps. Every time.

    Hands on

    Cloud in a Jar

    20 minutes · Do this with a grown-up nearby

    You need

    • a clear glass jar
    • warm tap water
    • a plate
    • ice cubes
    • a flashlight

    Do this

    1. Pour about an inch of warm water in the jar, with an adult.
    2. Swirl the water so the jar warms.
    3. Set the plate on top and put ice cubes on it.
    4. Shine a flashlight through the side of the jar.
    5. Watch the air near the plate.
    6. Take off the plate and see what rises.
    Write or draw: Draw the jar and arrows for warm air rising and cool air at the top. Write what you saw.

    Watch for: A thin fog forms where warm, wet air meets the cold plate. That is a small cloud.

    Safety: Have an adult handle the warm water. Do not use hot water from a kettle.

    Same every time

    Three rules

    Rule 1Weather is what the air does now.

    It can change in hours.

    Rule 2Clouds mean water vapor has cooled.

    Cooling turns vapor into drops.

    Rule 3Warm, wet air makes bigger storms.

    Lots of vapor means lots of rain.

    Grandpa Fenn’s notebook

    Say it like a scientist

    weather
    What the air is doing at a place and time.
    humidity
    How much water vapor is in the air.
    cloud
    Tiny water drops or ice crystals gathered in the sky.
    front
    The edge where two kinds of air meet.

    Poppy’s quiz

    Six questions

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

    Talk about it

    Say it out loud

    • What evidence could you gather to predict rain tomorrow?
    • What kind of weather do you see most in your town? What part of the water cycle is behind it?
    Did you know

    A single puffy cloud can weigh over a million pounds. The drops are tiny, and the air holds them up.

    Someone who does this

    A meteorologist studies the air and tells people what the weather will be.

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