Heat energy can be defined as ______

• A. Temperature
• B. Mass
• C. Pressure
• D. Volume

Answer: (A)

Heat energy is closely tied to how hot something is, which we measure with temperature. Temperature represents the level of thermal energy in a substance: higher temperature generally means more thermal energy per unit of matter. When you add heat, the temperature rises (for a given material and amount), and when heat flows between objects at different temperatures, energy moves from the hotter to the cooler one until they balance.

Mass, pressure, and volume aren’t measures of heat energy themselves. Mass affects how much energy is needed to change the temperature, while pressure and volume describe how a system occupies space and the forces involved, but they don’t define the amount of heat energy present.