Teacher: For a learner who did not get there with <code>worksheet.html</code>. This is not a shorter version — it starts from things the learner has genuinely recovered with their own hands, and only names the two kinds of change in task 3. Four tasks, big boxes, and a worked example above each.
1 Take it apart and put it back — do it, then write
Worked example:Paper torn into four pieces. Can you put the pieces back into the shape of a sheet? Yes — line them up. <b>Is it still paper?</b> Yes.
What you did
Could you put it back?
Is it still the same material?
Crumpled a sheet of paper
Stirred sugar into water
2 Things you cannot put back — you may have watched these at home
Worked example:Bread toasted brown. Can you make it white again? No. <b>Is it still bread?</b> Not quite — the brown part is something new, and it smells different.
What happened
Could you put it back?
Is it still the same material?
An egg was fried
A banana went black
3 Now the two words — look at your last column in tasks 1 and 2
Worked example: Still the same material → physical change. A new material → chemical change. Crumpling paper is a physical change.
From tasks 1 and 2
Physical or chemical
Crumpled paper
Sugar in water
Fried egg
Blackened banana
Notice which column you used. It was the <b>last</b> one, not the middle one.
4 Getting it back on purpose — match each mixture to a way of separating it
Worked example:Stones in rice. You can see them and they are big enough to hold. Method: picking.
The mixture
How you would separate it
Sand in water
Salt in water
Iron nails in sawdust
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> · yes / yes · you cannot pick the sugar out, but it is still there — yes to the material. | <b>2</b> · no / no · no / no. | <b>3</b> · physical · physical · chemical · chemical. | <b>4</b> · let it settle and pour the water off, or filter it · let the water evaporate · use a magnet.<br><b>The middle column in tasks 1 and 2 is deliberately unreliable</b> — sugar in water can be recovered but not by hand. The last column is the one that decides, and task 3 is where the learner notices.