thermal energy is what form of energy
Heat (Thermal energy). Matter is made up of particles or molecules. These molecules move (or vibrate) constantly. A rise in the temperature of matter makes the particles vibrate faster. Thermal energy is what we call energy that comes from the temperature of matter. The hotter the substance, the more its molecules vibrate, and the therefore the higher its thermal energy. For example, a cup of hot tea has thermal energy in the form of kinetic energy from its vibrating particles. When you pour some milk into your hot tea, some of this energy is transferred from the hot tea to the particles in the cold milk.