What is temperature a measure of?

Temperature is a measure of the average kinetic energy of particles in a substance. When temperature increases, the particles move faster, which indicates that the average kinetic energy of the particles is higher. This relationship is fundamental in understanding thermal energy and the behavior of matter. In solids, liquids, and gases, the movement of particles varies with temperature, affecting states of matter and thermal interactions.

While the other options mention different properties of matter, they do not accurately define temperature. The average mass of particles is related to their identity and does not directly correlate with temperature. Energy contained within an object can relate to several forms of energy, including potential and kinetic energy, but it is not a precise measure of temperature itself. Finally, pressure is influenced by temperature but is a separate property, primarily relating to the force exerted by particles when they collide with the walls of their container, rather than their kinetic energy.