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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 5 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: Chocolate melted, then cooled, Milk left until it curdles, Water boiled into steam under a lid, 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: A cake baked from batter, Ice cream left out and refrozen, Clay fired in a kiln, Wax melted in a warm dish

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

Sort: Butter melted in a pan, Water frozen into ice, Wood burnt to ash, Bread toasted

Can be changed backCannot be changed back

LessonPrint · 2-PS1-4 · Set 5 · free to copy for classroom use

Answer key — Back Again, or Not

Set 5. Prints on its own sheet.

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