Kinetic Theory: Kinetic Energy – JSS2 Basic Science Lesson Note (Second Term)

The Kinetic theory of matter assumes that matter is made up of tiny particles such as atoms, molecules, and ions that are continually moving and therefore possess kinetic energy.

A British Scientist, Dalton, about  1806AD, expanded the idea of atoms. He made various statements about the nature of atoms. His ideas about atoms are stated below:

1. Matter is made up of minute indivisible particles called atoms.
2. Atoms cannot be created or destroyed.
3. All the atoms of an element are alike and different from the atoms of all other elements.
4. Atoms combine in small whole numbers to form new substances.

 All these ideas collectively form Dalton’s atomic theory. Since Dalton’s atomic theory was proposed, scientists have accepted the idea that matter is made up of particles.

Kinetic energy is the energy a body has by its motion. The kinetic theory of matter assumes that the particles that makeup matter have energy and that these particles are in constant motion.

Assumptions of the kinetic theory

The basic assumptions of the kinetic theory deal with energy due to the movement of particles and it includes:

1. Matter is made up of tiny indivisible particles that are in constant motion and therefore possess kinetic energy.
2. An increase in heat supply or increase in temperature, causes an increase in the motion of the particles and thus, an increase in the average kinetic energy of the particles.
3. An increase in kinetic energy of the particles due to an increase in heat supply brings about a change in state viz solid, liquid, and gas.