Define matter. Briefly describe the physical classification (three different stages) of matter.

Matter. Matter is defined as anything which occupies space and has mass. On the basis of physical state, it has been classified as solids, liquids and gases.
(i) Solids are rigid substances which have definite shape and possess definite volume. For example, table, book, silver, wood etc.
(ii) Liquids are those mobile substances which have no definite shape but possess definite volume. They take up the shape of the vessel in which they are put. For example, milk, water, oil, mercury etc.
(iii) Gases are those mobile substances which have no fixed shape or volume. Gases flow to assume the shape of the container. For example, nitrogen, hydrogen, carbondioxide etc.