This theory has 3 basic assumptions. The molucules are in constant motion. This motion is different for the 3 states of matter. Solid - Molecules are held close to each other by their attractions of charge. Liquid - Molecules will flow or glide over one another, but stay toward the bottom of the container.
Motion is a bit more random than that of a solid.
Gas - Molecules are in continual straightline motion. The kinetic energy of the molecule is greater than the attractive force between them, thus they are much farther apart and move freely of each other. When the molecules collide with each other, or with the walls of a container, there is no loss of energy. Some experiments involving the 3 states of mater are explained at smiles site Home Page of Poseidon Software and Invention. Poseidon Software and Invention.