Science Fenns K-5Grades K to 5
A glass of clear water on a kitchen counter with a spoon, a pile of salt and a pile of sand beside it.

Science / All lessons / Matter and Mixtures

Solutions

When a solid seems to disappear.

Lesson 11 of 40

Try this first

Before we start

Today’s story

Solutions

Jess stirs sugar into iced tea on a hot afternoon. The sugar vanishes. The tea tastes sweet. A few minutes later she stirs another spoon. This time a little sugar sits at the bottom of the glass.

A solution is a mixture where one thing spreads out evenly in another. The one that dissolves is the solute. The one that does the dissolving is the solvent. Sugar is the solute. Tea is the solvent. You cannot see the sugar, but you can taste it.

Not everything dissolves. Sand does not. Oil does not. And a liquid can hold only so much. Warmth and stirring help the sugar dissolve faster. Here are the steps.

See it

Five steps. Every time.

    Hands on

    Does It Dissolve

    25 minutes · Do this with a grown-up nearby

    You need

    • Five clear cups
    • Room temperature water
    • Salt
    • Sugar
    • Sand
    • Flour
    • Baking soda
    • A spoon
    • Notebook

    Do this

    1. Pour the same amount of water in each cup.
    2. Predict which solids will dissolve.
    3. Add one spoon of salt to the first cup and stir for ten seconds.
    4. Do the same for each solid in a different cup.
    5. Look for clear or cloudy water.
    6. Look for solids left at the bottom.
    7. Wait five minutes and look again.
    Write or draw: A table with Solid, Prediction, Dissolved yes or no, and Notes.

    Watch for: Notice which cups look clear and which are cloudy. Notice that cloudy water might be a mixture and not a solution.

    Safety: Do not taste anything and wash hands when done.

    Same every time

    Three rules

    Rule 1A solution looks clear and even.

    Look for the same everywhere.

    Rule 2Dissolved is not gone.

    The solid is still in there.

    Rule 3Test, do not guess.

    Some solids surprise you.

    Grandpa Fenn’s notebook

    Say it like a scientist

    dissolve
    To spread out evenly in a liquid until you cannot see the bits.
    solute
    The solid that dissolves in a solution.
    solvent
    The liquid that does the dissolving.
    solution
    A mixture that is the same all the way through.

    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 sugar is still in the tea?
    • What do you stir into a drink at home or on the ranch?
    Did you know

    Ocean water is a solution. Salt is spread out in it, which is why it tastes salty.

    Someone who does this

    A pharmacist mixes medicines that must dissolve evenly in a liquid.

    BeforeMixturesNext lessonMatter Is Conserved