|Class 7 Chemistry Physical and Chemical Changes||What are changes|
What are changes??
Any alteration of a substance from its original shape, size and state is known as a change. But the changes occurring around us can sometimes be reversed and sometimes cannot. Those changes which can be reversed are termed as reversible changes like rolling of roti, melting of ice, melting of wax. Whereas those which cannot be reversed are termed as irreversible changes like cooking food, baking cake, baking roti, tearing paper and many more.
The changes can again be classified into two types namely physical and chemical changes as discussed below.