Question

2. Distinguish between fast and slow changes. Give two examples of each type.
Give two examples each of reversible and irreversible change.
State some of the irreversible biological changes that take place in nature.
5. Give one example of a physical change in which (i) energy is given out
(ii) energy is absorbed.​

Answer 1

Answer:

Distinguish between fast and slow changes.

Fast changes occur with in seconds or minutes. Whereas slow changes take place very slowly and may take hours, days or months to complete. Examples for fast changes: Burning of paper, Burning of a candle. Examples for slow changes: Rusting of iron, Germination of seed, curdling of milk etc.

Give two examples each of reversible and irreversible change.

Reversible changes - where a change is made physically and can be undone or reversed. For example: freezing water to make ice. Irreversible changes - where the change is made chemically and can't be reversed into its original states. For example: baking a cake.