A change is the process in which something becomes different from what it was earlier. It is the observable difference between the initial state and the final state of any substance. Change is the law of nature – in our day-to-day life we see many changes around us. This chapter classifies changes as slow/fast, reversible/irreversible, physical/chemical, desirable/undesirable and natural/human made, and explains dissolution, solute and solvent.
1. What Is a Change?
- Weather changes periodically (daily/seasonly) and seasons change periodically.
- A paper burns readily, while it takes a few days for an iron nail to rust.
- It takes a few hours for milk to turn into curd, but vegetables get softened in a few minutes when cooked.
What happens during a change?
Changes are accompanied by change in properties like shape, colour, temperature, position and composition. Some changes can be observed while some are not possible to notice.