What does heat energy result from?

Heat energy results from the random movement of molecules. In any substance, molecules are in constant motion, and this motion can vary in speed and direction. The kinetic energy associated with this random motion is what constitutes heat energy. Essentially, as the temperature of a substance increases, the molecules move more vigorously and collide with one another more frequently, leading to an increase in thermal energy.

This motion can be understood in terms of temperature: higher temperatures indicate greater molecular movement, which translates to higher kinetic energy and, therefore, more heat energy being present in the system. The randomness of this movement is key; it's not organized or consistent, but rather chaotic, leading to variations in energy distribution that contribute to the overall thermal energy of the system.