Examples of Reversible Changes:
1. Melting of Ice into water. By freezing the water we can obtain ice again.
2. Folding a paper: By unfolding it, we can undo the change.
3. Hot milk to cold milk: By boiling milk, we can make it warm.
Example of Irreversible Changes:
1. Burning of candle.
2. Bursting of crackers.
3. Cutting of trees.