What is thermal energy?

Thermal energy refers to the total kinetic energy of the particles in a substance. This energy arises from the motion of particles—atoms and molecules—within the material. As particles move, they collide with each other, transferring energy. The faster the particles move, the higher the temperature of the substance, indicating that there is more thermal energy present.

In this context, it’s important to distinguish thermal energy from related concepts. While potential energy stored in chemical bonds forms the basis for chemical reactions, it does not define thermal energy. Similarly, kinetic energy of particles refers only to the motion of the particles, but thermal energy encompasses the collective kinetic energy of all the particles in a substance, not just their motion taken individually. Position-based energy is also distinct, as it relates to gravitational or elastic potential energy, which does not factor into the thermal properties of a substance.

Thus, the definition of thermal energy correctly captures the essence of the movement and interactions of particles, making the total kinetic energy measurement the accurate representation of thermal energy in the context of physics and chemistry.