Do not confuse temperature and heat
Temperature is related to heat but is different from it.
Heat is the energy associated with the motion of the atoms or molecules of which everything is made. The more energetic the atoms are, the faster they move (in a gas or liquid) or the more vigorously they vibrate (in a solid).
Heat is the amount of thermal energy an object contains, measured in joules (J).
Application of heat causes the temperature to rise – except that when it melts a solid or boils a liquid, the temperature remains constant!
Heat and temperature are different because the heat energy in a large object is greater than that in a small object, even when their temperatures are the same.
Further ideas about temperature and its significance in physics came through the second law of thermodynamics, which considers the fundamental limits to the conversion of heat into work.
The second law shows how a ‘thermodynamic’ (absolute) temperature can be derived as a fundamental parameter of physics and chemistry, independent of any arbitrary material property (like the expansion of mercury in glass, or the resistance of a platinum wire). A physically meaningful temperature scale is based on thermodynamic principles.
