Science Fenns K-5Grades K to 5
A kitchen counter with a bowl of water holding a cork floating and a washer sunk, and a magnet touching a paper clip.

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Magnets and Sinkers

Which things stick to a magnet? Which sink or float?

Lesson 9 of 41

Try this first

Before we start

Today’s story

Magnets and Sinkers

Rosa has a magnet and a bowl of water. She tests a paper clip. It sticks. She drops it in. It sinks.

She tests a cork. It does not stick. It floats. Each thing has its own properties.

A property is something you can observe or measure. The steps show how to test two of them.

See it

Five steps. Every time.

    Hands on

    Stick or sink

    25 minutes · Do this with a grown-up nearby

    You need

    • Bar magnet
    • A bowl of water
    • Paper clip
    • Coin
    • Cork
    • Pencil
    • Wooden craft stick
    • Paper towel

    Do this

    1. Gather six small objects.
    2. Predict for each if it will stick and if it will float.
    3. Hold the magnet to each object.
    4. Write stick or no stick.
    5. Place each gently in the water.
    6. Write float or sink.
    7. Dry things and put them back.
    Write or draw: A table with predictions, magnet results and float results.

    Watch for: Notice that being heavy does not decide floating. Some small things sink.

    Safety: Keep magnets away from phones and computers. Do not put anything in your mouth.

    Same every time

    Three rules

    Rule 1Predict before you test.

    It shows you what you already think.

    Rule 2Test one thing at a time.

    That keeps results clear.

    Rule 3Record each result.

    You can look back at the pattern.

    Grandpa Fenn’s notebook

    Say it like a scientist

    magnet
    An object that pulls on iron and some other metals.
    property
    Something you can observe or measure about an object.
    float
    To stay on top of water.

    Poppy’s quiz

    Six questions

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

    Talk about it

    Say it out loud

    • Which object surprised you? How do you know?
    • What things at home stick to the refrigerator?
    Did you know

    A huge steel ship floats because its shape holds a lot of air, so it is not simply a block of steel.

    Someone who does this

    A recycling worker uses magnets to pull steel cans from other trash.

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