Charles' Law
The effects of temperature on the volume of the gas was studied by Jacques Charles in 1787 and Gay Lussac in 1802 at constant pressure for different gases. Their conclusion can be given as Charles' law which states that at a constant pressure, the volume of a given amount of gas is directly proportional to the absolute temperature.
According to Charles’ Law, the volume of a gas increases as its absolute temperature is being raised, if its absolute temperature is lowered, its volume will consequently decrease.
V ∝ T
V1/T1 = V2/T2
Graphical representation of Charles’ Law is a straight line pointing away from the origin of the graph.
At –273ºC, the volume of the gas is reduced to zero - the gas ceases to exist. This temperature (–273ºC) at which the gas hypothetically ceases to exist is called Absolute zero. It is represented by zero K. This is the theoretically lowest possible temperature. In actual practice, you cannot reduce the temperature of the gas to zero kelvin.
Kelvin Scale of Temperature
The scale of temperature which has –273ºC as zero is called Kelvin Scale. Degree celsius is converted to Kelvin by adding 273. For example 15ºC can be converted in K by adding 273 to 15.