DIY Project
About

Science

Sink or float tub

A tub of water and a basket of household objects for guessing, testing and sorting what sinks and what floats.

Sink or float tub
LevelBeginner
AgesAges 3 to 5
Time30 minutes
Cost$0, uses what you have
SummerOutdoorsRainy day

What you'll need

Materials

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How to make it

Safety

Stay right there the whole time and empty the tub when done, since young children can drown in a few inches of water.

  1. Step 1: Fill the tub
    1

    Fill the tub

    Fill the tub halfway with water. Set a towel underneath.

  2. Step 2: Make a chart
    2

    Make a chart

    Draw 2 columns on paper: a boat for float and an anchor for sink.

  3. Step 3: Guess first
    3

    Guess first

    Hold up an object. Ask, "Sink or float?"

  4. Step 4: Test it
    4

    Test it

    Have your child drop it in and watch.

  5. Step 5: Sort it
    5

    Sort it

    Put the object on the right side of the chart.

  6. Step 6: Find surprises
    6

    Find surprises

    Try an apple. Most kids guess it sinks, and it floats.

Edie's tip

Add a ball of foil, then squish it flat into a boat shape. Same foil, different result.

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