Particle model — Describe

How is the temperature of a substance related to the motion of its particles, and what is absolute zero?

The higher the temperature of a substance, the greater the average kinetic energy (and speed) of its particles. As a substance is cooled, particle motion decreases, and at absolute zero (-273°C, equal to 0 K) the particles have the minimum possible kinetic energy. This is the lowest temperature that can theoretically be reached.