The kinetic-molecular theory of gases is the theory that gases are made up of a large number of small particles (atoms or molecules), all of which are in constant, random motion. The rapidly moving particles constantly collide with each other and with the walls of the container. Kinetic theory explains macroscopic properties of gases, such as pressure, temperature, or volume, by considering their molecular composition and motion.

Video segment. Assistance may be required. Watch the following slide show to view animations of gas particles as they pertain to the kinetic molecular theory.

The following online animation explains the main components of the molecular kinetic theory.

This activity might not be viewable on your mobile device. Interactive exercise. Assistance may be required. The Structure of Matter