Chapter 4 - Air Pressure

Question 1

What is Air pressure?

Answer 1

Pressure exerted by the weight of air

Question 2

What directions does air pressure exert?

Answer 2

In all directions (up, down and sideways).
Air pressure is balance, when air pressure pushes down on an object it equally pushes up onto the object.

Question 3

What is a Barometer?

Answer 3

A device used for measuring air pressure.

(Note: when air pressure increases, the mercury in the tube rises. When air pressure decreases, the mercury column falls.)

Question 4

What is the result of horizontal differences in air pressure? And how?

Answer 4

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

Question 5

What causes pressure differences on Earth’s surface?

Answer 5

Unequal heating.
(Solar radiation is the ultimate energy source for most wind.)

Question 6

What are the 3 factors that combine to control wind?

Answer 6

Pressure differences
Coriolis effect
Friction

Question 7

What is a pressure gradient?

Answer 7

The amount of pressure change occurring over a given distance

Question 8

Explain closely spaced isobars.

Answer 8

(Lines on a map that connect places of equal air pressure)
Indicate a steep pressure gradient and high winds.

Question 9

Explain widely spaced isobars.

Answer 9

Indicate weak pressure gradient and light winds.

Question 10

What is the Coriolis effect?

Answer 10

How Earth’s rotation affect moving objects.
(Northern Hemisphere: Free flowing objects or fluids move right of their path motion.
Southern Hemisphere: Free flowing objects or fluids move left of their path motion.)

Question 11

What is friction?

Answer 11

Acts to slow air movement, which changes wind direction.