Notes
Earth's structure and landforms
- Earth's layers: crust, mantle, liquid outer core, solid inner core. Tectonic plates move at divergent, convergent and transform boundaries.
- Convergent boundaries build mountains and cause subduction; transform boundaries cause earthquakes. The Pacific Ring of Fire has many volcanoes and earthquakes.
- Weathering, erosion and deposition shape landforms: canyons, floodplains, deltas, fjords and dunes.
Climate and biomes
- Weather is short-term; climate is the long-term average. Climate depends on latitude, elevation, nearness to water, currents, winds and mountains (rain shadow).
- Temperature falls about 3.5°F per 1,000 feet of elevation.
- Biomes include rainforest, savanna, desert, steppe, temperate forest, taiga and tundra.
Water and hazards
- About 71 percent of Earth is water; about 3 percent of Earth's water is fresh, mostly frozen.
- Tropical cyclones are called hurricanes, typhoons or cyclones depending on the ocean. Tsunamis often follow undersea earthquakes.
Topics in this unit
Each topic has its own short notes and practice.
Practice
Plates moving apart form a divergent boundary, like the Mid-Atlantic Ridge.
$8 \times 3.5 = 28$°F cooler, so about 47°F.
Climate describes the typical long-term pattern.
Savanna is grassland with scattered trees and distinct wet and dry seasons.
Air descending the leeward side has already lost most of its moisture.
Only about 3 percent of Earth's water is fresh, and most of that is ice.
Free response
Write your answer first, then open the scoring guide.
Free-response question
A country sits on the western coast of a continent. A tall mountain range runs along its coast. Warm winds blow in from the ocean, and the country is near an active plate boundary.
(a) Explain how the mountain range creates a wet side and a dry side.
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Winds blowing from the ocean rise over the mountains, cool and drop rain or snow on the windward (ocean) side. The air then descends on the far side with little moisture, creating a dry rain shadow.
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(b) Name one natural hazard likely in this country because of the plate boundary and explain why.
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Earthquakes (or volcanoes) are likely because plates colliding or sliding past each other build up stress and release it suddenly, or melt rock to form magma.
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(c) A town in this country is at 6,000 feet and a town at sea level has an average temperature of 72°F. Estimate the high town's average temperature and name the factor involved.
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$6 \times 3.5 = 21$, so about $72 - 21 = 51$°F. The factor is elevation.
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