Thermal Energy : A Substance Or System

3594 Words Jan 3rd, 2015 15 Pages
Kelly McManus

Physics Honors

Block 1

January 5, 2015

Thermal Energy

Thermal energy is the energy a substance or system has related to its temperature. This means the energy of moving or vibrating molecules. Atoms and molecules are always in motion. Generally the motion of thermal energy cannot be seen, but instead the effects it has on the substance can be seen or felt. Thermal energy can have several different uses. It can be used to heat homes, cook food, and generate electricity.

Thermal energy, however, is not the same as heat. Heat is energy transferred between substances or systems due to a temperature difference between them. Therefore it is correct to say that a system contains thermal energy, but it is incorrect to say that it "contains" heat. This is because heat refers to energy that is transferred from one thing to another. The quantity of heat transferred by a substance is reliant on on the speed and number of atoms or molecules in motion. The faster the atoms or molecules move, the higher the temperature. The more atoms or molecules that are in motion, the greater the amount of heat they transfer.

Temperature is a measure of the average kinetic energy of the particles in a body. Temperature can be understood by recognizing that a hot object contains more thermal energy than a cold object. The amount of thermal energy in a substance is affected by the amount of particles that are in it. Temperature is independent of number of particles in…
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