Thermal Energy and Gases
What happens to the volume of gas when
thermal energy changes?
Have you ever placed the metal lid of a jar under
hot water so it would open more easily?
Why do you think this works?
LAB: Growing Air
Lab Extention
Dry ice is actually frozen carbon dioxide. Carbon dioxide
freezes at -78.5 C at standard temperature and pressure .
What do you think would have happened if the flask had been
placed in frozen carbon dioxide instead of frozen water?
Jacques Charles
Jacques Charles was a French scientist who described the
relationship between temperature and volume of a gas.
Charles’s practical experience with gases was most likely the
result of his interest in balloons.
His result led him to describe the relationship between
temperature and volume of a gas, now known as Charles’s law.
Charles’s Law (Volume-Temperature Law)
Charles’s law states that the volume of a gas increases with
increasing temperature, if the pressure is constant.
Thermal Contraction
Thermal contraction is a decrease in a volume as its
temperature decreases.
Thermal Expansion
An increase in a volume as the temperature increases is
called thermal expansion.
Remember
The number particles does not change during expansion and
contraction.
The object that the particles are in changes size as the
thermal energy changes. This is due to the space between the
particles changing.
Each particle does not change in size.