Science Fenns K-5Grades K to 5
A frozen puddle at dawn on a Texas gravel road, with a child holding a melting ice cube in a cup.

Science / All lessons / Stuff and What It Is Like

Melting and Freezing

Heat it and watch. Cool it and watch.

Lesson 11 of 41

Try this first

Before we start

Today’s story

Melting and Freezing

Nina leaves an ice cube on the counter. It gets small. A puddle forms. She wipes it up. Where did it go?

The ice did not vanish. Heat from the room turned the solid into a liquid. That is melting. If she cools the liquid enough, it becomes solid again. That is freezing.

Warming and cooling can change the state of matter. The steps show how to predict it.

See it

Five steps. Every time.

    Hands on

    Melting race

    25 minutes · Do this with a grown-up nearby

    You need

    • Three ice cubes of the same size
    • Three plates
    • A timer
    • A sunny windowsill
    • A shady spot
    • A bowl of warm tap water
    • Paper

    Do this

    1. Place one cube on each plate.
    2. Put one in the sun, one in the shade, and one in a bowl of warm water.
    3. Predict which melts first.
    4. Start the timer.
    5. Check every two minutes and write what you see.
    6. Record the time each cube is gone.
    7. Compare.
    Write or draw: A table with place, prediction and melting time.

    Watch for: Notice the cube in warm water melts fastest.

    Safety: Use warm tap water, not hot. Mop up any water.

    Same every time

    Three rules

    Rule 1Heat makes solids melt.

    The hotter it is, the faster it melts.

    Rule 2Cold makes liquids freeze.

    Cold takes heat away.

    Rule 3The matter stays the same stuff.

    Melted ice is still water.

    Grandpa Fenn’s notebook

    Say it like a scientist

    melting
    When a solid turns into a liquid.
    freezing
    When a liquid turns into a solid.
    state change
    When matter changes from one state to another.

    Poppy’s quiz

    Six questions

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

    Talk about it

    Say it out loud

    • How did you predict which cube melts first? How do you know you were right?
    • Where have you seen freezing or melting near home?
    Did you know

    Water is unusual. Ice floats, which is why ponds freeze from the top down.

    Someone who does this

    A weather forecaster tells farmers when freezing will happen so they can protect crops.

    BeforeSolid, Liquid or GasNext lessonBoiling and Condensing