Figure 8-2.Temperature comparison.
The boiling point of water is 100°C and
To summarize, conversion formulas are as
212°F. The difference between the boiling point
and the freezing point of water is 100° and 180°F.
See figure 8-2. Therefore, within this span on the
thermometers, 1°C equals 1.8°F.
However, temperature readings on either scale
are taken in respect to the number of degrees
below or above zero, thus 320 must be added to
the 180°F in order to obtain the total reading from
the Fahrenheit zero point. Substituting these
values into the conversion formula (°C x 1.8)
+ 32, we have (100° x 1.8) + 32° = 212°F.
If we wish to convert Fahrenheit degrees to
centigrade degrees, the algebraic order of calcula-
tion must be reversed and we find that (°F 32°,
+ 1.8 = °C. Substituting the values we find (212°
32°) + 1.8 = 100°C.
EBULLITIONThis is probably the most
common process involving heat. The term merely
means boiling, to wit, raising the temperature of
a liquid to the point where it changes to vapor
or steam. All liquids have a definite temperature
at which this occurs, a factor called the boiling
point and the basis for separation from other
liquids by distillation.
Boiling is used extensively in compounding,
since in most cases the volubility of the prepara-
tion is increased. As an example, consider making
instant coffee with cold water compared to using