Which of the following best defines thermal energy?

Thermal energy is best defined as the energy that arises from the motion of atoms and molecules. This form of energy is directly related to the temperature of a substance; as the temperature increases, the kinetic energy of the atoms and molecules within the substance also increases. This motion can be in the form of vibrations, rotations, or translational movements, all contributing to the overall thermal energy of that object or substance.

In contrast, energy stored in chemical bonds refers specifically to the potential energy that is released or absorbed during chemical reactions, which does not directly relate to thermal motion. Energy due to an object's height is related to gravitational potential energy, a different concept altogether, while energy from stretched materials is connected to elastic potential energy, which pertains to materials that can deform upon application of force. The focus on the motion and kinetic aspects of atoms and molecules encapsulates the essence of thermal energy, making this definition the most accurate among the options provided.