# Movement of Air Chapter 14-4

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Movement of Air Chapter 14-4
California Standard 5.a. & b.

Temperature Differences
Temperature differences on Earth are caused by the tilt of the Earth relative to the sun. Therefore, different parts of the Earth receive more solar radiation than others.

With less energy to heat the poles, than the equator, the temperature is lower at the poles.
More solar radiation at the equator than at the poles converts into higher temperatures at the equator.

Thus, more solar radiation at the equator means:
1. Air above the equator is hotter. 2. The air is less dense. 3. Therefore, the air moves upward. 4. As this air moves up it is replaced by cooler air. 5. Thus you have convection currents.

Convection Currents

Where does this cooler air come from?
From the N and S poles silly! Duh! Remember Santa doesn’t wear that full length Santa suit because he’s trying to get a tan.

Ho… ho…ho… and what would you like for Christmas
Ho… ho…ho… and what would you like for Christmas? A stocking full of coal? Ho…ho…ho.

The Four Seasons The reason there are seasons on Earth is because of the tilt of the Earth. This tilt is 23 ½ degrees. When the northern hemisphere is tilted away from the sun you have the winter and when it is tilted towards the sun you have summer.

N hemisphere away from sun
Winter S hemisphere towards the sun

N hemisphere towards the sun, summer
S hemisphere away from the sun, winter

So… the reason there are seasons is because of the tilt of the Earth
So… the reason there are seasons is because of the tilt of the Earth. This is a quiz, benchmark and district final question. Now you know the answer.

The Coriolis Effect 1. The coriolis effect causes air and water to move to the right in the northern hemisphere and 2. to move to the left in the southern hemisphere. 3. This effect causes distinct water and wind patterns.

The Coriolis Effect In a nut shell, the Coriolis effect is the movement of atmospheric air and ocean waters due to the rotation of the Earth on it’s axis.

The Surface Winds 1. Between 0 and 30 degrees N and S latitude are the trade winds, while 2. between 30 and 60 degrees N and S latitude are the westerlies.

The Winds (Coriolis Effect)

The rotation of the Earth causes the water and the wind to move in certain directions. This movement creates distinct patterns of movement which can be used by sailing ships and airplanes.

The Mayflower ship and the colonization of America

The Doldrums Doldrum: 1) A region of the ocean near the equator, characterized by calm, light winds. 2) Someone who is unhappy, depressed, etc.

The Doldrums Doldrums

High Altitude Winds 1. High altitude winds or jet streams are narrow belts of wind which can blow from 97 to 185 km/hr. 2. Airplane pilots use these winds to move around the world. 3. Change from day to day and season to season.

Daily and Seasonal Winds
1. A convection current is when a large body of water meets a large land mass which can result in convection currents. 2. Solar radiation warms the land faster than the water so the air over the land moves upward being replaced by the air over the water.

Sea and Land Breezes 1. When the air moves from the land to the sea it is called a land breeze. 2. When the air moves from the sea to the land it is called a sea breeze.

Sea Breezes

Land Breezes

The End

Quick Quiz 1. The __________ are responsible for the movement of much of the weather across the United States. a. prevailing westerlies b. polar easterlies c. trade winds d. doldrums

2. The deflection of wind, or Coriolis effect, from the north and south poles is due to
a. Rotation of the Earth b. The shape of the Earth c. The tilt of the Earth on it’s axis d. The total land mass in North America.

3. Temperature differences on Earth are caused by ___________.
a. the rotation of the sun b. the closeness of the sun to the Earth c. the tilt of the Earth on it’s axis d. the distance to the sun during the summer.

4. Air above the equator is heated more than at other places on Earth because the sun’s rays strike Earth _________ at the equator. a. at a low angle b. at a tilt c. directly d. at a 45 degree angle

5. When the land is heated faster than the ocean the result is a
a. land breeze b. sea breeze c. directional breeze d. none of the above

Well… how’d you do?