Which object has less thermal energy?
an 800-gram rock at a temperature of 270°F an 800-gram rock at a temperature of 250°F
The objects are identical except for their temperatures.
All solids, liquids, and gases are made of matter. Matter is made up of tiny particles that are always moving. The energy from the motion of these particles is called thermal energy.
Temperature measures how hot or cold matter is. If the particles in matter slow down, the temperature goes down. The matter now has both less thermal energy and a lower temperature.
The two rocks have the same mass but different temperatures. Since the 250°F rock is colder than the 270°F rock, it has less thermal energy.