Sink, Float, Predict · Connected Through Play

Mary Nunaley

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10d (edited) • Play Ideas & Prompts

Sink, Float, Predict

@Gus Gray

, I had your kids in mind for this one since they like water!

@Sarah Cooper

let your son know we are doing science all week. Starting easy and building.

Today we’re starting with a simple kitchen science classic: sink or float. It looks easy, but it opens the door to prediction, observation, testing, and a lot of “wait… why did that happen?”

Gather Your Gear:

Large bowl, dish tub, or sink filled with water
Spoon
Apple
Grape
Ice cube
Small toy
Aluminum foil
Paper towel
Towel for spills
A few extra household objects safe for water testing

Steps:

Before placing each item in the water, have everyone make a prediction:“Will it sink or float?”

Test each item one at a time.

After each test, pause and talk:

Was the prediction correct?
What surprised you?
What do the floating objects seem to have in common?
Did any heavy things float?
Did any small things sink?

Write down predictions and results if your kids enjoy tracking data. This is a great time to introduce the concept of a science or lab notebook.

The goal is not to rush toward the “right answer.” The goal is noticing patterns and asking better questions as you go.

The Twist:

Now start changing the objects.

Cut the apple into pieces.
Freeze or thaw items.
Flatten aluminum foil, then crumple it into a ball, then shape it like a boat.

Test the same material in different shapes and compare the results.

Variations by Age:

Ages 3–6

Keep this one sensory and playful. Encourage describing words:

Squishy
Smooth
Heavy
Tiny
Cold

Count down before dropping objects and celebrate the surprises together. If attention starts fading, let them choose the next object to test.

Ages 7–12

Turn this into a real investigation. Before testing, ask kids to sort the objects into two groups:

“Will Float”
“Will Sink”

After testing, challenge them to revise their thinking.

Then move into a mini design challenge, using only aluminum foil, create a floating boat that can hold:

5 pennies
10 pennies
20 pennies

Test different boat shapes and compare results.

Ask:

Which shape worked best?
Why did some boats sink faster?
What changed when weight was added?

If they enjoy competition, let family members build different designs and compare outcomes. Don’t forget to record observations in your notebook.

Ages 13–17

Shift this from simple prediction into experimental thinking. Challenge them to answer a bigger question:“What actually affects whether something sinks or floats?”

Have them identify variables: