What is the definition of temperature in relation to molecular activity?

Temperature is defined as a measure of the average kinetic energy of molecular vibrations within a substance. This concept stems from the kinetic theory of matter, which describes how temperature reflects the energy associated with the motion of particles. As molecules vibrate, move, or translate more rapidly, the temperature of the substance increases, indicating higher molecular activity.

In simpler terms, temperature provides insight into the energy state of a system; the higher the temperature, the greater the kinetic energy and the more vigorous the motion of its molecules. This understanding is fundamental in thermodynamics and helps to explain various physical properties of materials and their responses to heating and cooling processes.