1. Atmospheric Moisture
Earth Science

2. Warm Air Cold Air Moisture in the Air
Humidity is the moisture in the air.
Warm Air
Cold Air

3. Humidity Warm Air Cold Air Particles are far apart. . .
Thus the air has low density . . .
The farther apart the particles, the more moisture the air can hold
Particles are close together. . .
Thus the air has high density . . .
The closer the air particles, the less moisture the air can hold

4. Relative HUMIDITY
Ratio of air’s actual water vapor content compared to the amount it can hold
To find/calculate:
Measure the wet and dry bulb temperatures.
Find the difference between the two temperatures.
Use the dry bulb temperature and the difference between the two bulbs to look up the relative humidity on the chart provided.

5. Dew Point
Dew point temperature is the temperature at which an air mass is saturated (holding as much as it can) with water and will begin to condense.
Example: Air Temperature = 85F
Dew Point = 55F
Once the temperature reaches 55F, then dew (condensation) will form on surfaces (cars, grass, etc.).