The antiquated Farenheit temperature scale is only still used in a few countries (including the United States). Water freezes at 32^oF and boils at 212^oF. A much more natural temperature scale, called Celsius or Centigrade, rates the freezing and boiling point of water at 0^oC and 100^oC respectively. To convert between the two scales use

where F is the temperature in Farenheit and C is the temperature in Centigrade.

Example If you set your house thermo state to 70^oF what is the temperature in Centigrade ?

Solution  

Example At what temperature are the Farenheit and Centigrade scales equal ?

Solution When they are equal the F = C = x giving

i.e.

The temperature of a substance is related to the speed of the individual molecules which also give rise to pressure. Thus a gas which has fast moving molecules will have a high temperature and pressure. What happens if we slow all the molecules to zero speed? Well then the gas pressure will be zero. The temperature at which this happens is -273:15^oC. This leads to a third type of tmperature scale called Absolute temperature or Kelvin temperature. The Kelvin temperature at which a gas has zero pressure is defined to be 0^oK. Thus

where C is the temperature in Centigrade and K is the temperature in Kelvin.

Example What is the relationship between Farenheit and Kelvin?

Solution

and

giving

or