The subject is natural environments the atmosphere
Explain the processes involved when water changes state
Use a psychrometer or hygrometer and appropriate tables to determine the relative humidity and dew-point temperature of the air
Explain the adiabatic process and its effect on cooling and warming the air
Calculate the temperature and relative humidity changes that take place in air as the result of adiabatic cooling
Describe the global patterns of precipitation and its variability. Explain why relative humidity does not give an accurate indication of the actual
amount of water vapor in the air. [1 pt]
Air is saturated when it contains all the water vapor that it can hold at a particular temperature.
The temperature at which saturation occurs is called the dew-point temperature. Put another way, the dew-point is the temperature at which relative humidity is 100%.
A kilogram of air at 25°C, containing 5 grams of water vapor had a relative humidity of 25% and was not saturated. When the temperature was lowered to 5°C, the air had a relative humidity of 100% and became saturated. Therefore, 5°C is the dew-point temperature of the air in the example.
By referring to Table 1, what is the dew-point temperature of a kilogram of air that contains 2 grams of water vapor? [1 pt]
Dew-point temperature = _______________°C
What is the relative humidity and dew-point temperature of a kilogram of air at 20°C that contains 3.5 grams of water vapor? [2 pt]
Relative Humidity = _______________%
Dew-point temperature = _______________°C
If the air parcel in question 25 retains its water vapor content and decreases to 10°C, what is the new relative humidity and dew-point temperature? [2 pt]
Relative Humidity = _______________%
Dew-point temperature = _______________°C
Is the air parcel in question 26 approaching saturation? Explain. [2 pt]
How many grams of water vapor will condense on a surface if a kilogram of air at 86°F with a relative humidity of 100% is cooled to 59°F? Refer to Table 1. [1 pt]
___________ grams of water will condense
Assume a kilogram of air at 30°C contains 10 grams of water vapor. Using Table
Determine how many grams of water vapor will condense out if the air’s
temperature is lowered to each of the following temperatures. [2 pt]
15°C: ____________ grams of condensed water
5°C: ____________ grams of condensed water
When condensation occurs, what three (3) conditions must be achieved in the atmosphere? (Hint: Look in previous sections for the answers) [3 pt]
