What makes climate, and the world's biomes

Grade 9 Social Studies Worksheet

Circle the best answer.

1. Read this first

   Six places and their settings

   Place	Latitude	Setting	Average yearly temperature (°F)	Precipitation a year (inches)
   Seattle	47.6°N	west of the Cascade Range, near the Pacific	53.7	39.3
   Yakima	46.6°N	east of the Cascade Range	50.8	8.0
   Lima	12.1°S	Pacific coast, near sea level, cold Humboldt Current offshore	68.9	0.3
   Salvador	13.0°S	Atlantic coast, near sea level, warm current offshore	78.1	72.2
   Quito	0.2°S	9,350 feet above sea level	57.4	43.3
   Belem	1.5°S	near sea level, 33 feet	80.3	130

   Note: Averages are 1991-2020 normals. Moist air rises over mountains and drops rain on the windward side; the higher the range, the more rain falls on its windward side and the drier the lee side. Warm ocean water makes the air above it rise and form rain; cold water cools the air above it and makes it stable, so little rain forms. Air cools about 3.5°F for each 1,000 feet of height. A biome is a large area whose plants and animals suit its climate: forest where precipitation is high (Seattle), shrub-steppe where it is low (Yakima), desert on a cold-current coast (Lima), tropical rainforest in the hot, very wet lowlands (Belem). On west coasts between about 30° and 45° latitude, winds bring rain in winter and sinking dry air in summer, so summers are dry. Inland places behind high ranges get little rain in every season. Four graphs (invented). Graph P: January 50°F, July 65°F; rain 6.0 inches in the wettest month, December, and 0.2 inch in the driest, July. Graph Q: January 48°F, July 64°F; rain 3.2 inches in December and 2.4 inches in August. Graph R: January 30°F, July 74°F; rain 1.4 inches in May and 0.6 inch in January. Graph S: January 31°F, July 72°F; rain 4.1 inches in July and 2.0 inches in February. Three stations (invented): from 1980 to 2020 the average summer high rose 3°F at a city airport, 1°F at an orchard 5 miles outside the city, and 1°F at a ridge station 3,000 feet higher. Paved surfaces in cities hold heat.

2. 1.

   Seattle and Yakima lie about 1° apart with similar average temperatures, yet Yakima gets 8.0 inches of precipitation to Seattle's 39.3. What explains the gap, Ari?

   • The Cascade rain shadow: Pacific air drops rain on the west side; Yakima lies in the lee
   • A cold current off the coast, which dries Yakima but leaves Seattle a wet place
   • Elevation: Yakima is higher, which explains both its cooler air and its one-fifth rainfall
   • Latitude: Yakima lies 1° farther south, so it is warmer and drier than Seattle is
3. 2.

   Lima and Salvador lie about 1° apart near sea level. Lima averages 68.9°F and 0.3 inch of rain, Salvador 78.1°F and 72.2 inches. What explains it, Bo?

   • Distance from the ocean: Lima lies inland, so the sea cannot warm or wet it
   • Ocean currents: cold water off Lima steadies the air; warm water off Salvador does not
   • Latitude: Salvador lies nearer the equator, so it is warmer and wetter than Lima is
   • Elevation: Lima lies higher than Salvador, so it is cooler and drier than Salvador
4. 3.

   Higher mountains leave their lee drier. If the Cascades were 3,000 feet lower, what does Jun predict for Yakima and its dry biome?

   • Yakima would get more precipitation, and the dry biome would shift east of it
   • Seattle would get less rain, but Yakima would keep its 8.0 inches, since the lee is unchanged
   • Nothing would change, since Yakima and Seattle would stay on the same latitude as before
   • Yakima would get less precipitation, and the dry biome would spread west toward Seattle
5. 4.

   Cold water steadies the air and warm water makes rain form. If the Humboldt Current warmed by several degrees, what does Kira predict for Lima?

   • Warmer, wetter air, so the coastal desert biome would shrink
   • Cooler, drier air, so the coastal desert biome would spread farther inland than before
   • Warmer but just as dry, since the mountains behind the coast alone decide the rainfall
   • No change, since a current is just a surface flow and cannot affect rain on land
6. 5.

   Air cools 3.5°F for each 1,000 feet. If the climate around Quito warmed by 3.5°F, how far would a zone of any given temperature move, Luz?

   • About 1,000 feet downslope, since warmer air sinks and the zone moves down with it
   • About 100 feet upslope, since 3.5°F is a small change on a mountain 9,350 feet high
   • About 3,500 feet upslope, since the temperature change in degrees gives the distance in feet
   • About 1,000 feet upslope, since 3.5°F of warming matches 1,000 feet less height
7. 6.

   A place sits inland at 45° north, behind a high range that blocks ocean air. Noah chooses between Graph R and Graph S. Which fits?

   • Graph S: its summers are warm at 72°F, and a warm summer fits an inland place
   • Neither: a place at 45° should be as wet as Graph P, which has a wettest month of 6.0 inches
   • Graph R: it is dry in every month, never above 1.4 inches, and warm in summer
   • Graph S: its July rain of 4.1 inches shows ocean air is crossing the range
8. 7.

   Which fact shows that Graph P has a dry season and Graph Q does not, Pia?

   • The January temperature, 50°F against 48°F, since the warmer winter marks the dry graph
   • The driest month: P gets 0.2 inch in July, while Q still gets 2.4 inches in August
   • The wettest month, 6.0 inches against 3.2, since the wetter peak shows a dry season
   • The July temperature, 65°F against 64°F, since the warmer summer marks the dry graph
9. 8.

   The airport station's summer high rose 3°F; the orchard and the ridge each rose 1°F. About how much of the airport's rise does Ren link to the city?

   • About 4°F, the airport's rise plus the 1°F rise seen outside the city
   • The whole 3°F, since the airport station lies in the city and paved surfaces hold heat
   • About 2°F, the airport's 3°F rise minus the 1°F seen at stations outside the city
   • About 1°F, the rise seen at the orchard and at the ridge
10. 9.

    Tala says the ridge's 1°F rise shows the city added nothing. The ridge is 3,000 feet higher, about 10.5°F cooler. What is wrong with that?

    • The ridge is 10.5°F cooler, so its change cannot be compared with the airport's change
    • Nothing: stations at different heights show the same change, so the city adds nothing
    • The ridge shows change outside the city; the city's effect is the airport's extra 2°F
    • The ridge lies outside the city, so its 1°F shows natural variation caused the whole rise
11. 10.

    Natural variation raised all three stations by about 1°F. What share of the airport's 3°F rise does Zee link to human-built surroundings?

    • About one-third, the 1°F that all three stations share
    • About two-thirds, the 2°F left after the 1°F that all three stations share
    • About half, since 3°F splits evenly between natural change and the city
    • All of it, since a station in a city cannot show natural change at all