Water in the Atmosphere

Review:

How does water get into the atmosphere?

Heat EnergyHeat Energy

Condensation

CloudsRainSnowSleetHail

HUMIDITY

The amount of water vapor in the air

WARM air can hold MORE water than cold air

This is why . . .Hot August days feel

“muggy.”Your skin dries out in the

winter.Phoenix is more

comfortable than Orlando

How does sweating cool your body?

Where in the world does sweating NOT cool your body?

Tropical jungleUltra-hot desert

RELATIVE HUMIDITY

The % of water in the air compared to how much water the air could hold

PSYCHROMETER

Tool used to measure relative humidity

Psychrometer

Dry bulbWet bulb

The DIFFERENCE between the 2 is used to calculate Relative Humidity

Steps to calculate Relative Humidity:1.Measure dry-bulb temperature2.Measure wet-bulb

temperature.3.Subtract the two to determine

the difference.4.Use a relative humidity table

to determine % of water vapor in the air.

Example:

1.Dry = _____2.Wet = _____3. Difference = _____4.Go to table: