Change of a bud into a flower is a change which cannot be reversed. Give four more such example.
Four examples of changes which cannot be reversed are:
1. Bursting of a blown balloon. The balloon loses its original shape, which cannot be brought back.
2. Baking of a cake, where the flour used cannot be got back in original powder form, once it is heated.
3. Cutting of a paper to make an aeroplane, boat, etc.
4. Burning of a candle, which includes both physical and chemical changes, which cannot be reversed.