Humidity

[Kenneth Sloane]

                      Subject:                              Time:  4:33 PM
  OFFICE MEMO         Humidity                              Date:  2/8/96

Think of any room or auditorium that has a pi#005#ano in it as an enclosure in
a sealed environment. The sealed environment is the outside world which,
depending on the atmospheric conditions of the outside world at any given time
in any region, has a certain volume of water vapor in it. Depending on the
temperature of the air, it can hold only a certain amount of moisture. If for
a particular temperature it is holding 50% of the water vapor it is possible
to hold, then the relative humidity of the air is 50%. Now since warmer air
can hold more water vapor, if we do not change the absolute amount of water
vapor in the air and make the air warmer, that air will try to get moisture
from anything around it that has moisture in it (the relative humidity goes
down) -- for example: ponds or lakes nearby, moisture in the soil, and also
the piano in that room or auditorium. We use this phenomenon to our advantage
to dry out wood in kilns; i.e. by creating an artificial sealed environment
around the wood. If we make the air colder, the reverse is true.

Ken Sloane, Oberlin Consevatory