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.

   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?

   • Elevation: Lima lies higher than Salvador, so it is cooler and drier than Salvador
   • Latitude: Salvador lies nearer the equator, so it is warmer and wetter than Lima is
   • Ocean currents: cold water off Lima steadies the air; warm water off Salvador does not
   • Distance from the ocean: Lima lies inland, so the sea cannot warm or wet it
3. 2.

   Quito and Belem both lie within 2° of the equator, but Quito is 9,350 feet up. Quito averages 57.4°F, Belem 80.3°F. What does Esme conclude?

   • Rain explains it, since Quito gets 87 inches less than Belem and drier air is colder
   • Latitude explains it, since Belem lies nearer the equator than Quito and so is hotter
   • The rule fits exactly, since 9,350 feet at 3.5°F per 1,000 feet is the 22.9°F gap
   • Elevation explains most of the 22.9°F gap, but the rule gives about 33°F, so it is a guide
4. 3.

   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?

   • No change, since a current is just a surface flow and cannot affect rain on land
   • Warmer, wetter air, so the coastal desert biome would shrink
   • Warmer but just as dry, since the mountains behind the coast alone decide the rainfall
   • Cooler, drier air, so the coastal desert biome would spread farther inland than before
5. 4.

   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 upslope, since 3.5°F of warming matches 1,000 feet less height
   • About 1,000 feet downslope, since warmer air sinks and the zone moves down with it
   • About 3,500 feet upslope, since the temperature change in degrees gives the distance in feet
   • About 100 feet upslope, since 3.5°F is a small change on a mountain 9,350 feet high
6. 5.

   Milo must match a place on a west coast at 38° latitude, with cool wet winters and dry summers, to Graph P or Graph Q. Which fits?

   • Graph Q: it is wet in each month, which fits the wet winters better than P does
   • Graph Q: its temperatures, 48°F and 64°F, are lower, so it matches a cooler coast
   • Neither: both have December as their wettest month, so both fit wet winters equally
   • Graph P: its driest month, July, gets 0.2 inch, which fits a dry summer
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
   • Graph S: its July rain of 4.1 inches shows ocean air is crossing the range
   • 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
8. 7.

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

   • The wettest month, 6.0 inches against 3.2, since the wetter peak shows a dry season
   • The driest month: P gets 0.2 inch in July, while Q still gets 2.4 inches in August
   • The July temperature, 65°F against 64°F, since the warmer summer marks the dry graph
   • The January temperature, 50°F against 48°F, since the warmer winter 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 2°F, the airport's 3°F rise minus the 1°F seen at stations outside the city
   • About 4°F, the airport's rise plus the 1°F rise seen outside the city
   • About 1°F, the rise seen at the orchard and at the ridge
   • The whole 3°F, since the airport station lies in the city and paved surfaces hold heat
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?

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