Charles' Law

The volume of a gas is directly proportional to the temperature at a constant pressure.


For example, if you double the temperature from 100K to 200K, at a constant pressure, the volume will double as well. 

This means the following conditions are required:
  • The amount of gas is definite.
  • The pressure (in mmHg, atm, kPa, etc) is constant.
  • The gas is in a closed system. 

According to Charles' Law
  • As the volume increase, the temperature increases.
  • As the temperature decreases,  the volume decreases. 





The formula for Charles' Law is 





In the formula...

V1 =  The original volume of the gas
T1 =  The original temperature of the gas
V2 = The final, or new, volume of the gas
T2 = The final, or new, temperature of the gas 

History of Charles' Law: 

  • Created by Jacques Charles, a French balloonist who flew the first hydrogen balloon in 1783.
  • Charles experimented by filling five different balloons with the same volume of the five different gases and heated them each at the same time
  • As he was doing his experiment, Charles saw that the balloons grew proportionally
  • The final observation was not published until 1802 by Gay-Lussac
  • Lussac named the law after the original scientist, Jacques Charles.