The first assumption of the kinetic theory is that gas is made of identical molecules traveling in various directions. The second assumption is that the molecules do not lose energy when colliding with each other. The third assumption is that the energy transferred between the molecules is heat.

The kinetic theory of gases is based on a basic molecule of gas. It was developed by British scientist James Clerk Maxwell and Austrian physicist Ludwig Boltzmann. The kinetic theory was established in the 19th century and developed into an important concept of modern science.

The assumptions of kinetic theory bring the characteristics of gas molecules to a basic level. This allows for the measurement in a mathematical sense.