Grow & Play
An adult holds a large rounded wooden block over a shallow plastic tray while a child points to the water
Original illustration · Grow & Play
Science · 5–6 years · 12 min

Sink or float

Explore four illustrated examples, compare solid and hollow shapes, then record your own observation with a grown-up.

predictionexperiment

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before you begin

Ready in one minute

YOU WILL NEED
shallow unbreakable tray with a little room-temperature water, if usedtowelone large, smooth, checked water-safe object
THE GROWN-UP'S ROLE

Stay within arm’s reach and watch throughout. Handle objects gently, wipe spills and empty the tray immediately afterwards. Pictures alone are enough.

THE WHOLE GAME AT A GLANCE
  1. 1Choose one illustrated object and describe a detail before opening its example.
  2. 2Compare the clay ball and the hollow boat: keep material and amount separate from shape.
  3. 3For real water, let a grown-up check and handle one large water-safe object; record what you actually see.
WHAT THIS BUILDS

Separating a guess, an illustrated explanation and a real observation develops careful comparison without turning play into a score.

made for little hands

Printable activity

A4 · black & white friendly
GROW & PLAYA4

My sink-and-float observation sheet

Use only with a grown-up beside real water, or draw an idea without water. Choose your own checked objects. This blank sheet does not copy screen guesses or supply results.

Hollow terracotta clay boat with dry interior and its rim above the waterline
Illustrations, not your results
The same terracotta boat filled with water, below the surface
Illustrations, not your results

Object: draw or name it

My idea before looking

What we really noticed

Object: draw or name it

My idea before looking

What we really noticed

Object: draw or name it

My idea before looking

What we really noticed

What changed, or what shall we ask next?

slow down & try

How to play

0 / 3 complete
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ask along the way

What changed between the clay ball and the boat?

✺

why it helps

Separating a guess, an illustrated explanation and a real observation develops careful comparison without turning play into a score.

make it fit your child

One game, three levels

Start where it feels comfortable and change the challenge whenever curiosity changes.

MAKE IT EASIER

Choose one picture. Point to the waterline or listen to one explanation; predicting and finishing all examples are optional.

TRY A NEXT STEP

Compare the same amount of clay as a ball, a hollow boat and a boat with water inside. Describe which condition changed before proposing a real test.

a little laboratory of ideas

From a drawing to a shared discovery

Look together, describe one detail and leave room for a different result. The aim is to compare an idea with something you actually observe, not to get every prediction right.

With real water, a grown-up stays beside the child

  • An adult prepares a stable, shallow, unbreakable tray with a little plain room-temperature water and stays within arm’s reach, watching throughout. A shallow tray does not make water safe on its own.
  • Choose only large, smooth, intact, water-safe objects suitable for the child’s age. Leave out coins, caps, cork pieces, small or loose parts, glass, sharp or electrical items. Follow toy and material instructions.
  • Keep objects and water out of mouths. The adult places and retrieves objects gently; do not throw, push heads toward the water or add loads of tiny objects. Paper-only exploration is enough.
  • Wipe spills promptly. If the adult must leave, take the child too. Empty and put away the tray straight after the activity, and wash and dry the materials and hands.
Light wooden block floating with part of it below the waterline

A light wooden block

This block is drawn partly under water, with its top above the surface.

This example uses wood less dense than water. Part of the block displaces water while the water supports it. Different woods and water absorption can change a real result.

Where does the water meet the block?
What helps us notice?

Waterline: The surface meets the sides of the block; floating does not mean staying completely dry.

Material: This example is light wood. “Wood” is not a promise about every possible block.

Shape: The block is solid, not a hollow boat. The material is important in this example.

Solid steel spoon below the waterline resting at the bottom of the tray

A solid steel spoon

The steel spoon is drawn resting at the bottom.

Solid steel is denser than water. In this example the spoon moves down; the drawing is not a test of your particular spoon. A hollow or differently made object needs its own observation.

What tells you that the spoon is not floating freely?
What helps us notice?

Waterline: The whole spoon is below the surface and touches the bottom.

Material: This example is solid steel, not every item that looks shiny.

Shape: A familiar spoon shape does not turn solid steel into a watertight hollow hull.

Solid terracotta clay ball below the waterline at the bottom of the tray

A solid clay ball

The solid clay ball is drawn below the surface.

For this solid material, density is greater than water’s. A smaller solid ball of the same clay would not become less dense simply because it is smaller.

What could we change without changing the amount of clay?
What helps us notice?

Waterline: The ball is drawn below the waterline, touching the bottom.

Material: This is a model of clay denser than water. Not every product called modelling clay behaves identically.

Shape: The ball has no large hollow space to keep water out. Compare it with the boat.

Hollow terracotta clay boat floating, dry inside, with its rim above the waterline

The same clay, a boat

The boat is drawn floating, with its rim above water.

The hollow form can displace enough water before water comes over the rim. The amount of clay is unchanged. This drawing assumes an intact hull; a real boat might leak or sink.

What changed: the material, the amount of clay, or its shape?
What helps us notice?

Waterline: Water meets the outside of the hull, below its rim; the middle is dry in this drawing.

Material: The clay is the same material and amount as the ball in the paired example.

Shape: A broad hollow form makes room that water has not entered. This can change whether the object floats.

Same clay. A different shape.

These three drawings use the same amount of clay, denser than water. The last drawing also has water inside the boat. They are examples, not measurements or a boat-building guarantee.

Solid terracotta clay ball below the waterline in a cutaway tray

A solid ball

The solid clay ball is drawn below the surface.

A solid piece of this clay is denser than water. Changing its size alone does not change that material property.

Hollow terracotta clay boat with dry interior and its rim above the waterline

An open boat

The broad hollow boat is drawn floating, with its rim above water.

A broad hollow shape can push aside enough water to support the clay before the rim goes under. The clay itself has not become lighter.

The same terracotta boat filled with water, below the surface

Water inside

Water has entered the boat; this drawing shows it sinking.

The clay is unchanged, but water inside adds load. A boat can sink when water comes in. A real result also depends on its shape and leaks.

A real observation, one object at a time

  1. Prepare together

    A rounded wooden block or a large rounded metal spoon may be suitable after adult checks. Set a towel nearby. The clay drawings do not require you to use clay; only use an age-appropriate material whose maker confirms water use if you choose to extend the activity.

  2. Keep the idea separate

    Point, speak or draw what you think may happen. “I do not know yet” is useful too. The adult gently places one object in enough room to move without pressing it down.

  3. Look before explaining

    Is it near the surface, lower down, or touching the tray? Look from the side without putting a face near the water. Notice shape and air spaces. If something rests on the bottom, that is not evidence of floating freely.

  4. Record what really happened

    Draw the object and its position, or ask the adult to write. If you try again, keep the object and conditions as similar as you can and mention what you changed. Stopping after one observation is fine; empty the tray with the adult.

Four useful words

Float
Stay supported in the water, rather than resting on the bottom.
Sink
Move down through the water; an object may then rest on the bottom.
Material
What something is made from: for example wood, metal or clay.
Shape
How it is formed: solid, hollow, broad or narrow.

Questions for grown-ups

Do heavy things always sink?

No. Weight alone does not decide. For a solid object, comparing its density with water helps. A large piece of some woods can float while a much smaller solid steel object sinks.

How can a metal ship float?

A hollow hull encloses space and can displace enough water to balance its weight before its rim goes under. The whole ship, including its enclosed space, is different from a solid piece of metal. This is a simplified explanation, not a design calculation.

Will every wooden block or plastic object float?

No universal result is promised. The type of material, absorbed water, enclosed air, openings and shape can matter. Inspect an object and observe it rather than using its name as a guaranteed answer.

Our clay boat did something else. Was that wrong?

No. The drawing assumes a clay denser than water, a broad intact hull and no water entering it. Real modelling materials differ; a narrow shape, crack or water inside can change the result. Describe what you saw rather than copying the example.

Do we need water, clay or four completed tests?

No. You can compare the drawings, point to a waterline, ask one question and stop. A spoken idea or listening is participation. The number of pictures opened is not a learning score.

Original explanatory drawings · Grow & Play

a complete play guide

Make the moment meaningful

A simple rhythm for beginning, noticing progress and continuing another day. Sink or float — 12 min.

◷
12 minTOTAL TIME
✓
3CLEAR STEPS
✦
3SKILLS
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1OPEN QUESTION
1
GET READY · 1 min

Gather: shallow unbreakable tray with a little room-temperature water, if used, towel, one large, smooth, checked water-safe object.

2
PLAY & EXPLORE · 10 min

Choose one illustrated object and describe a detail before opening its example. Compare the clay ball and the hollow boat: keep material and amount separate from shape.

3
TALK TOGETHER · 1 min

What changed between the clay ball and the boat?

skills in this game

What your child practices

◎
prediction

Separating a guess, an illustrated explanation and a real observation develops careful comparison without turning play into a score.

↔
experiment

Following the steps connects an idea with an action and a result.

✦
Express

Explaining a choice grows language, confidence and reflection.

notice, do not test

Small signs of growth

These are invitations to notice—not a checklist your child must complete.

Starts one step with less help.

Stays curious after a surprise or tries another way.

Uses a new word, movement or idea to explain a choice.

words that open thinking

Three questions worth waiting for

Tap a question for a gentle follow-up. Ask just one, then leave room for the child's own idea.

NOTICEWhat changed between the clay ball and the boat?

Pause and wait. A child may need several quiet seconds.

COMPAREWhat changed after your try?

Ask: “What helped you notice that?”

IMAGINEWhat would you like to test next?

Let the child choose one small change for the next try.

Choose one question — there is no need to ask all three.

keep curiosity going

Try it a different way tomorrow

◡MAKE IT GENTLER

Choose one picture. Point to the waterline or listen to one explanation; predicting and finishing all examples are optional.

★LET THE CHILD LEAD

Invite your child to prepare one part, explain the rule and decide when the game is finished.

↗ADD A CHALLENGE

Compare the same amount of clay as a ball, a hollow boat and a boat with water inside. Describe which condition changed before proposing a real test.

remember the moment

A small note
for next time.

What made your child smile? Keep one thought here for the next play day.

Open the family notebook →
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