20.1 Air Masses

20.1 Air Masses

Earth Science 9th Grade

Quick Review from Chapter 19

• Air pressure is the pressure exerted by the weight of air. It is exerted in all directions.

• Air flows from areas of higher pressure to areas of lower pressure.

• The unequal heating of Earth’s surface generates pressure differences.

• Three factors combine to control wind: pressure differences, the Coriolis effect, and friction.

• Cyclones are centers of low pressure.

• Anticyclones are centers of high pressure.

Multiple Choice

An air mass is a large body of air with uniform temperature

and _______.

• Uniform moisture at any given altitude

• Same thickness

• Low pressure throughout

• Medium pressure throughout

Multiple Choice

An air mass changes

• The rotation direction of cyclones

• weather that is nowhere near it

• the weather of the area over which it moves

• the weather of a different area

Multiple Choice

In addition to their overall temperature, air masses are classified according to the surface over which they form.

• True

• False

Multiple Choice

Which air masses influence much of the weather in North

America, especially east of the Rocky Mountains?

• Maritime polar and continental polar

• continental polar and continental tropical

• maritime tropical and continental polar

Multiple Choice

What causes most of the precipitation in the eastern

two thirds of the United States?

• maritime polar air masses

• continental polar air masses

• continental tropical air masses

• maritime tropical air masses

Multiple Select

Check all of the following air masses.

• Continental polar

• Maritime Tropical

• Maritime Polar

• Continental Tropical

• Arctic Tropical