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Back Again, or Not is a free printable Grade 2 science worksheet on changes from heating and cooling that reverse and that do not, aligned to Common Core standard 2-PS1-4. It prints 3 questions with an answer key on its own sheet of paper, in 25 versions that each ask different questions, so no two pupils in the class work from the same page. Print it from the browser or download it as a PDF — no account, no email.

Set 20 of 25 · the same problems every time you open this link.

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One paper per pupil

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Set 1 has all 25 in a single PDF. All 25 sets ask different questions.

Back Again, or Not

2-PS1-4

NameDate

Sort each change into the right group.

1.Sort each one: Can be changed back or Cannot be changed back?

Sort: Water frozen into ice, Ice cream left out and refrozen, Bread toasted, An egg cooked hard

Can be changed backCannot be changed back
2.Sort each one: Can be changed back or Cannot be changed back?

Sort: Clay fired in a kiln, Wax melted in a warm dish, Chocolate melted, then cooled, Milk left until it curdles

Can be changed backCannot be changed back
3.Sort each one: Can be changed back or Cannot be changed back?

Sort: Water boiled into steam under a lid, Butter melted in a pan, Wood burnt to ash, A cake baked from batter

Can be changed backCannot be changed back

LessonPrint · 2-PS1-4 · Set 20 · free to copy for classroom use

Answer key — Back Again, or Not

Set 20. Prints on its own sheet.

  1. 1.1. An egg cooked hard — Cannot be changed back 2. Bread toasted — Cannot be changed back 3. Ice cream left out and refrozen — Can be changed back 4. Water frozen into ice — Can be changed back
  2. 2.1. Chocolate melted, then cooled — Can be changed back 2. Clay fired in a kiln — Cannot be changed back 3. Milk left until it curdles — Cannot be changed back 4. Wax melted in a warm dish — Can be changed back
  3. 3.1. A cake baked from batter — Cannot be changed back 2. Butter melted in a pan — Can be changed back 3. Water boiled into steam under a lid — Can be changed back 4. Wood burnt to ash — Cannot be changed back

More practice for 2-PS1-4

Argue with evidence that some changes from heating or cooling undo and some do not.

Teaching this next? Back Again, or Not is the 50-minute plan for it, with the misconceptions to expect.

All Grade 2 worksheets

Last reviewed 2026-09-05. Aligned to 2-PS1-4 of the Next Generation Science Standards.