Physical change.
It is a temporary change in which only the physical properties of a substance change i.e. change in colour, size, length, etc. This is therefore, a physical change. Physical change can be reversed by reversing the conditions. No new substance is formed in such a change.
Examples : Melting of wax, freezing of water into ice, magnetization of iron etc.
Chemical change.
A change in which new substances with one or more new properties are formed is called chemical change.
Examples : Burning of coal or wood, making of yogurt from milk, burning of magnesium ribbon, food spoilage, etc.
Differences between Physical and Chemical changes:
| Physical change |
Chemical change |
| (i) This is a temporary change. |
(i) This is a permanent change. |
| (ii) No new substance is formed in it. |
(ii) New substances with new properties are formed in it. |
| (iii) Products can be returned by simple methods. |
(iii) Products cannot be reversed by ordinary means. |
| (iv) No difference in the composition of the substance. |
(iv) Great difference in the composition of material. |
| (v) There is no energy change. |
(v) There is energy change. |
