---
title: "Reversible Changes"
description: "Demonstrate that dissolving, mixing, and changes of state are reversible changes where no new materials are formed"
canonical: https://lightmysky.com/learn/science/reversible-changes-mt_UKmtuAsSLN
source: https://lightmysky.com/learn/science/reversible-changes-mt_UKmtuAsSLN.md
retrieved: 2026-10-19
---

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# Reversible Changes

Demonstrate that dissolving, mixing, and changes of state are reversible changes where no new materials are formed

Subject: Science · Area: Matter & Materials · Ages 9 to 10
Page: https://lightmysky.com/learn/science/reversible-changes-mt_UKmtuAsSLN

## Ready when they can

- Define a reversible change as one where the original materials can be recovered
- Give at least three examples of reversible changes: melting, freezing, dissolving, evaporating
- Explain how to reverse each example (e.g. freeze melted chocolate, evaporate a solution)

## Lesson: Reversible changes: getting the material back

A reversible change is a change you can undo. Melt chocolate, then freeze it again, and you get chocolate back. Dissolve sugar in water, then let the water evaporate, and the sugar is still there. No new material forms. You get back exactly what you started with.

*(drawing: Ice melts to water, then freezes back to ice. Same water, no new material.)*

**Example.** Mia leaves a chocolate bar in the sun and it melts into a puddle. She puts the puddle in the freezer. An hour later, it is solid chocolate again, the same chocolate she started with.

*(drawing: Dissolve sugar in water, then let the water evaporate. The sugar crystals come back.)*

A change is reversible if you can get the exact same material back. If the change makes something completely new instead, it is not reversible, and no amount of cooling or waiting will bring the first material back. Notice the word can. A change stays reversible even when nobody actually reverses it: ice left in a warm room melts and usually nobody freezes it again, but freezing would work, so melting is still a reversible change.

**Recap.** Melting, freezing, dissolving, and evaporating are reversible changes: you can get the original material back, and no new material forms.

## Practice

24 questions on this page, each with its working shown.

## Needs first

- [Changes & Separation Vocabulary](https://lightmysky.com/learn/science/changes-and-separation-vocabulary-mt_ahSqW_kK1b)
- [Taking Apart & Rebuilding](https://lightmysky.com/learn/science/taking-apart-and-rebuilding-mt_GQpqoR5YOc)
- [Dissolving & Solutions](https://lightmysky.com/learn/science/dissolving-and-solutions-mt_Mf-T-fYRLX)
- [Heating & Cooling Changes](https://lightmysky.com/learn/science/heating-and-cooling-changes-mt_Pl-nsjYGZ3)

## Opens up

- [Physical vs Chemical Changes](https://lightmysky.com/learn/science/physical-vs-chemical-changes-mt_1hgck6ucII)
- [Irreversible Changes](https://lightmysky.com/learn/science/irreversible-changes-mt_rbPioPELM1)