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Zeroth law of thermodynamics
Premise: thermal equilibrium will be eventually reached (a matter of time) when two objects are put in thermal contact

Zeroth law:
two objects in thermal equilibrium with each other are at the same temperature

Temperature is the property that determines whether or not an object is in thermal equilibrium with other objects. It determines an object's hotness.







Kelvin is the absolute temperature scale.

Linear Thermal Expansion



The length of an object changes with its temperature changes:


SI unit:




Volume Thermal Expansion:

Heat and temperature change
Heat is energy that flows from a higher-temperature object to a lower-temperature object, because of their difference in temperature

SI unit: Joule (J)


The amount of heat Q that must be given to an object of mass m to increase its temperature by ΔT is
Q = cmΔT

The quantity c is called specific heat capacity, and is a characteristic of the substance.

SI unit: J/(kg°C)




One dietary calorie (food calorie) is a non-SI unit defined as the amount of energy needed to raise the temperature of 1 kg of water by 1 °C
1 cal = 4,186 J