1. Chapter 23 Section 1 Handout
Atmospheric Moisture

2. 1
The states in which water exists in the atmosphere are called:
Phases

3. 5 When does water change from one phase to another?
When heat energy is absorbed or released

4. 7
What phase does ice change into when it absorbs energy?
liquid

5. 8
When liquid water absorbs energy, it changes to:
A gas

6. 9 What happens to the water molecules when the water absorbs energy?
They collide more frequently

7. 10
The process in which the fastest-moving molecules escape from liquid and form invisible water is called
evaporation

8. 11
The name for heat energy that is absorbed or released during a phase change is:
latent heat

9. 12 When liquid water evaporates, the water:
absorbs energy from the environment

10. 14
The name for the process in which water vapor changes back into a liquid is:
condensation

11. 18 Through what process does most water enter the atmosphere?
evaporation

12. 19 Where on Earth does most evaporation take place?
In the oceans of the equatorial regions

13. 23
What is the name of the process in which a solid changes directly into a gas?
Sublimation

14. 24 Under what conditions might sublimation of snow and ice occur?
When the air is dry and the temperature is below freezing

15. 26
Humidity
Water vapor in the atmosphere

16. 27
Dew point
The temperature at which condensation equals evaporation

17. 28
Absolute humidity
The mass of water vapor contained in a given volume or air

18. 29
Mixing ratio
The mass of water vapor in a unit of air relative to the mass of the dry air

19. 30
What controls humidity?
Rates of condensation and evaporation

20. 31
What determines the rate of evaporation?
Air temperature

21. 32
What happens to the rate of evaporation as the temperature gets higher?
It also gets higher

22. 36
The measure of the actual amount of water vapor in the air is called the:
absolute humidity

23. 42
The ratio of the actual water vapor content of the air to the amount of water vapor needed to reach saturation is called:
Relative humidity

24. 43
If a person wanted to know how close the air is to reaching the dew point, he or she would calculate the:
Relative humidity

25. 46
What can make the relative humidity change even if the temperature does not change?
Moisture entering the air

26. 47
What can make the relative humidity increase if the moisture in the air remains the same?
A decrease in the temperature

27. 48
What happens to the relative humidity if the temperature increases as the moisture in the air remains constant?
The relative humidity will decrease

28. 50
What is the name of the condensation that forms during night?
dew

29. 51
What causes dew to form?
Objects near the ground lose heat during the night, often dropping to the dew point of the surrounding air. Air comes in contact with the surfaces and water vapor condenses out of it.

30. 57
Psychrometer
An instrument used to measure relative humidity consisting of two identical thermometer.

31. 62
What is the difference between the two thermometers of a psychrometer?
The bulb of one is covered with a damp wick and the bulb of the other remains dry

32. 63
What happens to the wet bulb-thermometer when the psycrhormeter is whirled through the air?
The water in the wick evaporates, and so heat is withdrawn from the thermometer.

33. 64
How does the temperature of the wet-bulb thermometer differ from that of the dry-bulb thermometer after the psychrometer is whirled through the air?
The wet-bulb thermometer is lower

34. 65
What would you use to calculate the relative humidity from a psychrometer?
The difference between the readings of the two thermometers.

35. The End