Shape Shadow Match
Your child stands a solid shape in a beam of light and works out which of the outlines traced on the paper its shadow belongs to.
- Age
- 3 to 6, best at 4
- Setup
- 2 min
- Play
- 10 to 20 min
- Materials
- Household only
- Mess
- None
- You
- Play along
Activity KG-A025
What you need
Half a dozen solid objects, a torch and a sheet of paper. The one thing worth getting right is the light, because a broad light source gives a soft-edged shadow that will not match anything.
- Four to six solid shapesx4 to 6 Or: a tin of beans, a mug, a dice, a matchbox, an egg and a cardboard tube. Or wooden blocks. The set needs flat-sided objects and at least one round one. A cube throws a square from every direction; a tin throws a circle from one direction and a rectangle from another. Put those two in the same set and the whole idea opens up on its own.
- A torchx1 Or: a phone torch. Or a low sun through a window in the late afternoon. A small bright source gives a hard edge that can be traced. A ceiling light, or a lamp with a shade, spreads the light so the outline fades out over a centimetre, and a fuzzy outline is the usual reason a shape will not sit on its line.
- Plain paper, A3 if there is anyx2 sheets Or: two sheets of A4 taped together along the long edge. Or the back of a roll of wallpaper. A shadow comes out bigger than the object, half as big again at a torch distance of about 30 cm. Six outlines on a single A4 sheet run into each other.
- A pencilx1 Or: a fine-tipped pen. Trace with a pencil. A thick marker line is wider than the error the child is trying to see, so near misses and exact fits look the same.
- Masking tapea few strips Or: a coin laid down to mark the spot. Tape the torch to the table. If it shifts 5 cm the shadows all change size and every outline you traced stops fitting, which looks like the child being wrong when it is the lamp.
How to set it up
- Half draw the curtains, or wait until after tea in winter.20 sec
- Tape the torch flat on the table, pointing across the paper, about 30 cm from where the shapes will stand.40 sec
- Stand each shape in the beam in turn and trace round its shadow, leaving a gap between outlines.60 sec
- Mix the shapes into a heap, slide the paper over and let her start wherever she likes.10 sec
What to say and what to do
Say
Find the one it fits.
Turn it round and watch what the shadow does.
- Say nothing at all when a tin makes a rectangle. That surprise is the activity, and it works better unexplained.
Do
- Trace the outlines yourself the first few times. Holding a shape steady in a beam and drawing round its shadow at the same time wants two grown-up hands.
- Put the tin in twice, once standing and once on its side, and trace both. Two outlines from one object is the best thing on the sheet.
- At the end, untape the torch and walk it backwards. Everything shrinking at once is worth three minutes on its own.
Let be
- Shadow puppets. Almost every sitting ends in hands and rabbits, and the shapes come back out tomorrow.
- A shape laid flat on the outline instead of stood up in the beam. Matching by eye is a real solve and it usually gets checked in the light a moment later.
- Square and rectangle used as the same word. At four they very often are.
What it looks like when it is working
- He turns the shape in the beam rather than carrying it from outline to outline.
- She says what the shadow will be before she stands the shape up.
- The tin gets picked up on purpose, because it is the one that does something.
- He asks to trace one himself, which is the point this stops being your puzzle.
What to expect at each age
At three
Matches three very different shapes when the outlines are the right way up, and tends to lay the shape straight onto the paper rather than standing it in the light.
Turning a shape to fit an outline that is lying at an angle arrives around four, once rotating something in the head has somewhere to start from.
Lasts 5 to 10 minutes
At four
Handles six shapes with outlines drawn at any angle, and rotates the object in the beam until the shadow lands. Notices that the tin does two different things and finds that interesting rather than annoying.
Predicting a shadow before casting it, and working out that moving the torch changes the size, both come around five.
Lasts 10 to 20 minutes
At five and six
Predicts the shadow, sets the puzzle for you, and works out that a shape held closer to the torch throws a bigger shadow than the same shape further back.
The difference between drawing round an object and drawing round its shadow is a good conversation at six or seven, and it is the start of how a drawing stands for a solid thing.
Lasts 20 minutes or more
When it goes sideways
Every one of these is the light telling you something rather than the child, and three of the four are fixed at the torch.
The shadow does not match any of the lines
The torch has moved since you traced. A few centimetres nearer makes every shadow noticeably bigger, and nothing on the sheet fits any more.
Tape it down, or draw round its base so it goes back in the same place. Re-trace one outline to check, then carry on.
The edges are blurry and nothing sits properly
The light source is broad rather than a point. A shaded lamp, a strip light or an overcast window all spread the shadow edge over a centimetre or so.
Use a phone torch, which is a small hard source, and move it back to about 50 cm. Pull the curtains halfway. The outline goes crisp immediately.
She names the shapes instead of matching them
Naming is the part she is confident about, so she is doing that instead. It is a fair trade and it means the matching is currently the harder half.
Turn the sheet a quarter turn so that no outline is the right way up. Naming stops being enough and the turning starts.
He says the tin's shadow is wrong
He is holding the name of the object against what it casts, and a round thing that makes a straight-sided shadow breaks that. This is exactly the idea the activity exists to open.
Leave the correction alone. Stand the tin on its end, then lay it down, then stand it up again, slowly, and let him watch the shadow change. Nobody needs to explain it.
Making it harder
Four rungs on the same torch and the same sheet of paper. The sheet gets redrawn each time, which takes two minutes.
Three shapes, outlines upright
- Ready when
- This is the starting point.
- What changes
- A ball, a cube and a tin, traced the right way up and well spaced.
- What is new
- The idea that a line on paper stands for an object at all.
Six shapes, outlines rotated
- Ready when
- He matches three shapes without help.
- What changes
- Six objects, and the outlines traced at whatever angle they fell.
- What is new
- Turning the object until the shadow fits, rather than walking round the paper.
One object, three shadows
- Ready when
- She rotates shapes to fit without being reminded.
- What changes
- Only the tin. Trace it standing, lying, and propped at an angle on a rubber, then hand her the tin.
- What is new
- That one thing has more than one shadow, and which one you get is something you choose.
She traces, you match, the torch moves
- Ready when
- He predicts a shadow correctly most of the time.
- What changes
- The child sets the sheet for you, and the torch is untaped and allowed to move near and far.
- What is new
- The size rule: closer to the light is bigger. That is the first properly physical idea in here.
Finish with the torch walking backwards across the room and every shadow shrinking at once. It is a better ending than a completed sheet, and it is the thing that gets asked for again next week.
How to keep it safe
One light and a handful of objects, and the light is the only thing worth a line.
- Use an LED torch or a phone torch rather than a candle or a desk lamp with a filament bulb. LEDs stay cool through a whole sitting.
- Tape the torch down pointing across the table at the paper. That keeps the shadows repeatable and keeps the beam out of everybody's eyes with the same piece of tape.
- If a shape is small enough to drop through a loo roll tube, keep it for a child past putting things in her mouth, or swap it for a mug and a cereal box.
Why this helps
A shadow is the outline of a solid thing flattened onto a surface, which is the same move a drawing makes and the same move a photograph makes. Four year olds meet flat pictures of solid objects all day and are rarely shown the step in between. Here the step is visible and reversible: stand the tin up, the shadow is a rectangle, lay it down, the shadow is a circle, and the tin never changed. That is the beginning of understanding that a picture is a point of view rather than the thing itself.
The hands are busy with something specific too. Matching a rotated outline means turning the object in the beam until it lands, which is trial and error to begin with and becomes prediction somewhere around five. Turning a shape in your head before you turn it in your hand is the skill underneath jigsaws, packing a box and reading a map, and this is one of the few places at four where it gets a clear right answer without anyone having to judge it.
Skill practised: turning a solid until its shadow lands on the line
Nobody is learning the word cylinder here. A four year old does this because the tin does a trick, and the geometry arrives behind it.
Where a set helps
The OtterDen Arch Set earns a place here because several of its pieces cast two completely different shadows. An arch reads as an arch from the front and a plain rectangle from the side; the half cylinder gives a semicircle one way and a square the other. That double answer is the thing this activity is built on, and most kitchen objects only manage it once. A tin of beans, a mug and a matchbox still make a good first set, so start there and see whether it takes before buying anything.
One a week, at your child's age
We publish one new activity a week at each age, in exactly this format. This is one to watch rather than read: a tin turning slowly in a beam, and the shadow going from circle to rectangle, takes about four seconds.
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Questions parents ask
Can we do this with sunlight instead of a torch?
Yes, and the edges are beautifully sharp. The catch is that the sun moves, so outlines traced at four o'clock will not fit at half past. Work fast, or trace and match within the same ten minutes. A torch taped to the table is the version that can be left out and come back to.
What objects work best?
A tin, a mug, a dice or small box, a matchbox, an egg and a kitchen roll tube make a strong six. You want flat-sided things and round things in the same set, because the contrast is what carries it. Avoid anything with a handle for the first few sittings; a handle makes the shadow hard to read.
The shadows come out huge. Is that a problem?
Only for the paper. A shadow is bigger than its object whenever the light is close, and the further back the torch goes the closer to life size it gets. Move the torch to about 50 cm and the outlines will fit on A4. The size change itself is worth showing on purpose later.
Is three too young?
Three works well with three very different shapes and the outlines traced the right way up. What usually is not there yet at three is rotating a shape to meet a tilted outline, so keep the sheet upright and the set small. The six-shape version at any angle suits four.