Temperature

Although all of us have an intuitive understanding of temperature, it is difficult to define precisely.  Heat, a form of energy, passes from a hot object to a cold one, and the amount of heat transferred depends on the difference in temperature between the two objects. There are several temperature scales in use today. In chemistry  (in the United States) you will need to be familiar with three.  These are the kelvin (K), Celsius (^oC), and the Fahrenheit (^oF) scales.  The Celsius and the kelvin scales each have the same size unit. Kelvin is an absolute temperature scale, that is it does not have any negative values.  The SI base unit of temperature is the kelvin (K). The kelvin scale is used in gas laws and thermodynamics.  A temperature of 300 K, (close to room temperature) would be read as "300 kelvins, not 300 degrees kelvin.

Zero on the Celsius scale would correspond to 273.15 K on the kelvin scale.  This makes it easy to convert between kelvin and Celsius with the equation.

K = ^oC + 273.15

The Fahrenheit temperature scale is widely used in the United States, both in everyday life and in industry and commerce.  A unit on the Fahrenheit scale is 5/9 the size of a unit on the Celsius scale.  In addition the two have different zero points, with zero on the Celsius scale being equal to 32 ^oF on the Fahrenheit scale.  Both these facts must be taken into account when converting from one of these scales to the other.  The equations which give the relationship between the two are

^oF = 1.8 ^oC + 32      and    ^oC = (^oF - 32) / 1.8