Humidity

A lot of people find that the general topic of moisture in the atmosphere is the most difficult of the topics in Introductory Physical Geography.  This little tutorial might help you understand the basics of these concepts a little better.

Water
Just a brief look at water and some of its properties.

Changes in State and Latent Heat
The physical states of water, and how energy is involved in changes of state.

Expressing Humidity
How do we describe the humidity of the air?  Here are several ways to express humidity, including everyone's favorite, relative humidity.  Also, a brief discussion of the relationship between humidity and temperature.

Adiabatic Processes and Lapse Rates
What happens to air when it is lifted?  It is very important to understand how adiabatic processes work, if you want to understand what happens to moisture in the atmosphere.

The Mountain
Most physical geography classes have that mountain.  Let's move up the mountain, lifting air up, cooling it off, wringing it out, then taking it down to the rainshadow on the far side.