Temperature Scales

Fahrenheit Celsius Kelvin
boiling point of water 212 F 100 C 373 K
body temperature 98.6 F 37 C
cool room temperature 68 F 20 C
freezing point of water 32 F 0 C 273 K
absolute zero
(molecules stop moving)
-273 C 0 K

Above, I have listed some key temperature reference points for the three scales.  As you can see, the Celsius scale is based on how water behaves, and, like all metric measurements, works around multiples of 10.

Converting Between Celsius and Fahrenheit Scales

To convert between Fahrenheit and Celsius, you need to visualize the "size of a step" represented by 1 degree.  Since there are 180 Fahrenheit steps between freezing and boiling and only 100 Celsius steps between freezing and boiling, Fahrenheit steps are about half as big. (They are exactly 5/9ths as big).  Can you draw a picture of this step concept?

Working from freezing, one can convert back and forth between the scales.  Here's an example:

A. Cool Room temperature is 68 F.   How many degrees Fahrenheit above freezing is this?

B. How many degrees Celsius above freezing would this be?  Well, these Fahrenheit degrees are 5/9 a Celsius degree, so:
36*5/9 = 20

C.  Since freezing is 0 C, the cool room is simply 20 C.

Note: While I am not going to hold you responsible for converting one temperature to another, I would like you to have a feel for this process.  You need to know the reference points on the chart above.

An simple conversion tool is available (along with a Boone Weather forecast) at http://www.weather.com/weather/us/zips/28608.html    (Look in the lower left of the page.)

Kelvin Scale

The size of a step represented by 1 degree Kelvin is the same as the size represented by 1 degree Celsius, but the 0 point is different.  This scale is used by scientists studying very cold temperatures.

© Appalachian State University
Science Education On-line
Dr. Leslie Bradbury and Mr. Jeff Goodman