What does thermal energy refer to?

Thermal energy refers to the total energy of motion in the particles of a substance. This concept is grounded in the kinetic theory of matter, which suggests that all matter is made up of tiny particles that are in constant motion. The energy associated with the movement of these particles contributes to the temperature and overall thermal energy of the substance.

In this context, as the particles move more vigorously, the thermal energy increases, leading to a rise in temperature. This understanding is fundamental in various scientific disciplines and is crucial for explaining phenomena such as heat transfer, changes of state, and the behavior of gases.

The other options do not accurately describe thermal energy. The energy stored in chemical bonds pertains to potential energy rather than kinetic energy related to particle motion. The energy of moving electrical currents relates to electrical energy, and while friction can produce heat, it is a specific process that generates thermal energy rather than a definition of what thermal energy itself is.