Reversible and Irreversible Changes

Reversible and Irreversible Changes

Some changes to materials can be undone (reversible), and some can't (irreversible).

Reversible changes

Melting, freezing, and dissolving are reversible — melted chocolate can be cooled back to a solid, and dissolved salt can be recovered by evaporating the water.

Irreversible changes

Burning, baking, and rusting are irreversible — you can't turn ash back into wood, or a baked cake back into raw batter. These changes often create a new substance entirely.

Practice

Is toasting bread a reversible or irreversible change? Why?