|The moisture content of the atmosphere varies over time and from place to place. This module examines some of the measures of atmospheric moisture and shows how these change as a result of diurnal changes or advection. An initial applet allows you to change the temperature and moisture characteristics of an air sample. Use it to explore the concepts of evaporation and condensation and to see how temperature and moisture content affect them. The applet also shows the relationship between temperature and saturation vapor pressure, and illustrates the concept of relative humidity. After experimenting with the applet, explore an example of diurnal temperature and relative humidity from Kansas City. In this example, you will be able to see how these variables change during the course of a day without temperature or moisture advection, and contrast this with days characterized by the advection of different air masses.