States of MatterGenerally, a given kind of matter exists in different physical forms under different conditions.
Example : Water exists as ice in solid form, water in liquid form and as steam in gaseous form.
To show that solid has definite shape
Take two flasks of different shapes. Place a wooden block in each. Now fill up each flask with water. What do you observe? You will notice that the wood even when placed in flasks of different shapes, did not change its shape.
A solid, such as a stone is hard. It cannot be compressed and has its own shape. It occupies definite (fixed) shape and definite (fixed) volume. A solid is almost incompressible and has fixed shape and volume.
The molecules are always in a state of random motion. The higher the temperature, the faster the molecules move. These molecules also have intermolecular attractive forces which are very strong, and are tightly packed. Because of the molecules being tightly packed, the spaces between them are very small. The molecules in these substances have very little movement. Such substances are in the solid state. The molecules in the solid state are tightly packed and the intermolecular distance is very small, so solids cannot be compressed easily.