Teacher: For a learner who did not get there with <code>worksheet.html</code>. This is not a shorter version — it uses people in a room as the particles, and only reaches dots on a page in task 3. Four tasks, big boxes, and a worked example above each. Tasks 1 and 2 need floor space; the corridor will do.
1 Be the particles — with five classmates, in an open space
Worked example:Solid. Stand in a neat square, shoulders touching, and rock gently on the spot. You are moving, but you are not going anywhere.
State
How you stood
How you moved
Solid
Liquid
Gas
2 What changed between them — answer for each move you made
Worked example: Solid → liquid: we broke the square but stayed touching, and we started sliding past each other. Nobody grew, and nobody left.
The move
What changed
Did anybody get bigger?
Solid to liquid
Liquid to gas
Nobody got bigger in either move. Write that down — it is the thing the drawings get wrong.
3 Now on paper — same size circles everywhere
Worked example: Trace round the same coin for every circle. If the circle changes size, the drawing is wrong, whatever the labels say.
Solid
Gas
Compare your two boxes. Only the <b>spacing</b> should be different.
4 Hot or cold — which way does the energy go
Worked example:Ice on a plate becomes water. Did you heat it or cool it? Heated. So energy went in.
What happened
Heated or cooled?
Energy in or out?
Water in a pan becomes steam
Water in a freezer becomes ice
Steam on a cold window becomes drops
This is where <code>worksheet.html</code> Section B begins. When a learner can do task 4 unaided, the bridge is finished.
Answer key — screen only, not printed.
<b>1</b> · Solid: neat pattern, touching, rocking on the spot. Liquid: close, no pattern, sliding past. Gas: far apart, moving fast across the space. | <b>2</b> · pattern broke, still touching / no; separated completely, moving fast / no. <b>Both 'did anybody get bigger' answers must be NO.</b> | <b>3</b> · same circle size, different spacing. | <b>4</b> · heated, in · cooled, out · cooled, out.