The kinetic theory explains the properties of different states of matter especially that of gases.
Its main points are as following:
1- Matter is made up of atoms, molecules or ions.
2- These atoms have kinetic energy due to which they are in state of motion.
3- In gas state molecules move in straight line, whereas in liquids and solids motion is very small.
4- Material particles generally have translational, rotational and vibrational type of movements.