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Name:____________________________________________ Date:____________________
Chapter 15 Study Guide
1. _________________________ refers to the present state of the atmosphere and describes current
conditions.
2. Important factors determining the state of the atmosphere are ___________________________,
__________________________, _______________________________, and the
______________________________________________________.
3. The amount of water vapor held in the air is called ___________________________.
4. The amount of water vapor that air can hold depends on the _______________________________.
5. __________________________________ is a measure of the amount of water vapor that air is holding
compared to the amount it can hold at a specific temperature.
6. When air contains as much moisture as possible at a specific temperature, it is
______________________________.
7. Saturated air has relative humidity of ______________________________.
8. The temperature at which air is saturated and condensation takes place is the
__________________________.
9. The dew point changes with the amount of _____________________ in the air.
10. Clouds are classified mainly by _______________________ and ___________________.
11. The three main cloud types are _____________________, _________________________, and
_____________________________.
12. ____________________________ clouds are associated with both fair weather and precipitation;
sometimes they form a dull, gray blanket.
13. When air is cooled to its dew point and condenses near the ground, it forms a stratus cloud called
_____________________.
14. _______________________ clouds are masses of puffy, white clouds, often with flat bases.
15. _______________________ clouds appear fibrous or curly. They are high, thin, white, feathery clouds
containing ice crystals.
16. _____________________ clouds are dark clouds associated with precipitation.
17. Water falling from clouds is called _________________________________.
18. ___________________________ determines what form of precipitation the water droplets fall in.
19. The four main forms of precipitation are: ____________________, __________________,
____________________, and ____________________.
20. _________________ forms when the air temperature is so cold that water vapor changes directly to a
solid.
21. _________________ forms when snow passes through a layer of warm air, melts, then refreezes near
the ground.
22. ________________ is precipitation in the forms of lumps of ice.
23. An ________________________ is a large body of air that has the same properties as the surface over
which it develops.
24. Variation in the atmospheric pressure affects the _______________________.
25. The boundary between two different air masses is called a ____________________.
26. ___________________ and ________________________ occurs at these fronts.
27. A __________________ front develops when a less dense, warm air mass slides over a departing cold
air mass.
28. A __________________ front happens when a cold air mass pushes under a warm air mass and forces
the warm air aloft along a steep front.
29. An __________________ front results from two cool air masses merging and forcing warmer air
between them to rise.
30. A _________________________ front occurs when pressure differences cause a warm front or a cold
front to stop moving.
31. In a ________________________, heavy rain falls, lightning flashes, thunder roars, and maybe hail
falls.
32. A ______________________ is a violent, whirling wind that moves in a narrow path over land, usually
in a direction from southwest to northeast.
33. Most tornadoes form along a _______________.
34. A ________________________ is a large, swirling, low pressure system that forms over tropical
oceans.
35. A ________________________ studies the weather.
36. A ___________________ is when conditions are favorable for severe weather, and you should take
caution.
37. A ___________________ is when severe weather conditions already exist, and you should find shelter.
38. The Service records the information on maps with a combination of symbols, forming a
____________________________________.
39. A line that connects points of equal temperature is called an ____________________.
40. An _____________________ is a line drawn to connect points of equal atmospheric pressure.
41. Isobars close together indicate ____________ winds.
42. __________________________ involves placing silver iodide or dry ice particles into clouds as nuclei
for water molecules to cluster around and freeze.