Contents Section1:ClimateFactors 1. Weather or Climate? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Elements of Climate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Factors Affecting Climate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4. Comparing Climates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 5. Quiz 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Section2:ClimateTypes 6. Climate Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 7. Asia and Australia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 8. Europe and Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 9. North America, South America, and Antarctica . . . . . . . . . . . . . . 32 10. Quiz 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Section3:ClimateEffects 11. Climate Affects People . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 12. Arctic and the Tropics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 13. Desert and the Mediterranean . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 14. What Is My Climate? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 15. Self Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 16. LightUnit Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Copyrighted material. May not be reproduced without permission from the publisher.

10

Lesson 3 Factors That Affect Climate

Vocabulary Wordscurrent: a stream of moving water in the oceanelevation: height above sea levelGulf Stream: a strong, warm ocean current that flows out of the Gulf of Mexico,

north along the east coast of the United States, and northeast across the Atlantic Ocean toward England

latitude: the distance north or south from the equator, measured in degrees Pronounce these words to someone.

You have now learned that climate is made up of four parts—temperature, air pressure, precip-itation, and wind . In this section we will study what causes a region to have the temperature, air pressure, wind, and precipitation it does . Latitude, elevation, bodies of water, and ocean currents are four of the main factors that affect climate .

LatitudeOne reason there are different climates is

because countries are at various distances from the equator or poles . On a globe, lines of latitude circle the earth . These lines measure the distance north or south of the equator . Latitude is a major factor in determining the climate of an area .

Latitude determines the amount of sunlight an area receives . The amount of sunlight then affects a region’s temperature . Areas near the equator receive more sunlight while the regions near the poles receive less . Lower latitudes near the equator are warm, while higher latitudes near the poles are cold .

While temperature is the most significant climate factor that latitude affects, latitude also affects the wind and precipitation of a region . Areas close to the equator receive little wind while the middle latitudes are affected by the trade winds and westerlies . A region near one of the three main precipitation belts experiences more precipitation . Areas outside of those three belts experience less precipitation .

ElevationElevation is the measure of distance above

sea level . Some places on the earth are below sea level . Some mountains and plateaus are miles above sea level .

Elevation affects climate in several ways . As you climb a mountain, the air becomes colder because it is no longer being warmed by the warm ground far below . The air is also colder because the thin air at high elevations holds less heat than thick air at lower elevations .

Elevation also affects the average air pressure of a region . Have you ever noticed as you drive up a mountain that your ears go shut or “plug”? That happens because air pressure drops as you travel up the mountain . This causes a differ-ence in pressure between the inside of your ear

Warm, moist air

Rain from expansionand cooling

Region of rain shadow

Evaporation fromcompression and

warming

Sea

Dry air

The rain shadow effect causes one side of a mountain to be drier than the other.

Rain Shadow Effect

Copyrighted material. May not be reproduced without permission from the publisher.

11

Lesson 3

and the atmosphere . As you come back down the mountain, the air pressure rises again . The popping sensation you may feel if you swallow or chew something is caused by the pressure equalizing between the inside of your ear and the atmosphere .

Mountains also affect the amount of rainfall or snow an area receives . A mountain range causes air to rise and cool . This causes clouds to form and precipitation to fall on the side of the moun-tain toward the sea . Because of this, the air has hardly any moisture remaining and the other side of the mountain receives little to no rain . This phenomenon is called the rain shadow effect. The dry area on the far side of the mountain is called a rain shadow.

Bodies of WaterLarge bodies of water affect the temperature,

moisture, and winds of a region’s climate . Water heats and cools more slowly than land . This creates uneven temperatures in the air over water and land, and produces pleasant land and sea breezes . You may notice that when you are near water, there is usually a breeze blowing .

Lands near large bodies of water have more moderate temperatures during the winter and summer than areas far inland . This occurs because in the winter, the body of water tends to be warmer than the air, and in the summer, it is cooler than the air . After the air is warmed or cooled by the water, it blows over the land, and moderates the tempera-ture . Areas near large bodies of water also tend to have higher humidity and receive more precip-itation because moisture from the lake or sea evaporates into the air .

Ocean CurrentsThe oceans are always moving .

Their movement may seem to be without design, but Psalm 8:8 tells

us there are “paths of the seas .” Matthew Maury spent forty years finding and mapping those paths of the seas . These paths are called currents and are like rivers of water flowing through the ocean . These ocean currents greatly affect the air above them, which in turn influences the climates of the regions nearby .

The Gulf Stream and the North Atlantic Drift are ocean currents that have the greatest effect on North America and Europe . The Gulf Stream is a river of water about fifty miles wide that starts in the Gulf of Mexico . As the Gulf Stream flows northward, it becomes what is known as the North Atlantic Drift . Notice the Gulf Stream and the North Atlantic Drift on the map .

The climates of the east coast of North America and Northern Europe are milder than would be expected because of this current . This is because, as the Gulf Stream and the North Atlantic Drift move northward, they carry heat from the warm waters of the Gulf of Mexico . This heat then warms the air above the current .

Other ocean currents around the world affect the climates near them—sometimes warming, sometimes cooling the land, depending on where the currents come from .

NorthAmerica

Africa

Europe

Iceland

Greenland

Gulf StreamNorth Atlantic Drift

Labrador Current

A t l a n t i cO c e a n

©M

ap R

esou

rces

The Gulf Stream

The Gulf Stream brings warm water northward.

Copyrighted material. May not be reproduced without permission from the publisher.

12

Lesson 3

Study Exercises Circle the letter(s) of the answer(s).

1. What are three ways latitude affects a region’s climate?a. windb. temperature

c. air pressured. precipitation

2. How does an increase in elevation affect air pressure and temperature?a. air pressure rises and temperature dropsb. air pressure drops and temperature rises

c. air pressure drops and temperature dropsd. air pressure rises and temperature drops

3. Which of the following would cause a warm climate?a. higher latitudeb. higher elevation

c. lower latituded. lower air pressure

4. What geographic feature causes the rain shadow effect?a. oceansb. mountains

c. lakesd. clouds

5. In what three ways does a body of water affect the climate of areas near it?a. increases air pressureb. produces more precipitationc. creates uneven temperatures that produce breezesd. keeps areas cooler in summer and warmer in winter

Answer the questions.

6. What are the four main factors that affect climate?

a.

b.

c.

d.

7. Why do a person’s ears “plug” when going up a mountain?

8. What is a rain shadow?

9. What makes some ocean currents warm and other cool?

10. How does the Gulf Stream affect the climates of eastern North America and Northern Europe?

Copyrighted material. May not be reproduced without permission from the publisher.

13

Lesson 3

Write true if the statement is true and false if it is false. Correct any false statements.

11. Latitude is the distance east or west of the equator.

12. Latitude is measured in inches.

13. Higher latitudes are generally cooler.

14. Elevation is the height above sea level.

15. Rain usually falls on the side of a mountain away from the sea.

16. An area in a rain shadow receives more than normal precipitation.

17. Land near large bodies of water tends to have less rainfall.

18. A stream or path of moving water in the ocean is a current.

19. Ocean currents do affect climate.

Looking Back Circle the letter of the answer.

20. Which of the following areas will warm up the slowest?a. parking lotb. grass-covered field

c. desertd. ocean

21. What occurs when air warms?a. it shrinks and pressure increasesb. it expands and pressure increases

c. it shrinks and pressure decreasesd. it expands and pressure decreases

22. What is normal air pressure at sea level?a. 1.47 psib. 14.7 psi

c. 147 psid. 0.147 psi

23. The ? are between 30° and 60° latitude.a. trade windsb. polar easterlies

c. doldrumsd. prevailing westerlies

Underline the correct choice.

24. The poles are colder than the equator because the sun’s rays are direct, slanted.

25. The humidity, weight from air pressing down causes air pressure.

26. Light and heat from the sun are forms of temperature, radiation.

27. Differences in pressure, precipitation cause wind.

Copyrighted material. May not be reproduced without permission from the publisher.

14

Lesson 3

Complete the statements.

28. Winds do not blow directly from high to low pressure areas because of the earth’s

.

29. We do not collapse from because our bodies have an equal amount pressing out.

30. A sudden windstorm that often brings rain or snow is a .

Did You Know? ‣ The Gulf Stream current moves at speeds of up to 5 .5 mph .

‣ Temperature decreases an average of 3 .5°F for every 1,000 ft gain in altitude .

‣ The volume of the Gulf Stream is much greater than all of the rivers that empty into the Atlantic combined .

Copyrighted material. May not be reproduced without permission from the publisher.