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

مواضيع ذات صلة

الديناميكا الحرارية الجزيئية

توزيع بولتزمان

العلاقات بين الخواص

القانون الثالث للديناميكا الحرارية

الطاقة الحرة

القانون الثاني للديناميكا الحرارية

القانون الأول للديناميكا الحرارية

Order and entropy

Irreversibility

The Clausius-Clapeyron equation

Internal energy

Entropy