Room 613 Social Studies Forms

Chapter 2 – Section 2  Physical Geography

Forces – The Earth’s Crust
 

The earths crust is made up of tectonic plates, huge slabs of rock up to 20 miles thick that float on top of hot molten rock called magma.
 

If two continental plates smash against each other, the collision produces high mountain ranges.

If a continental plate and an ocean plate move against each other, the continental plate slides over the denser ocean plate often causing a volcanic eruption.
 

When plates move alongside each other, faults or cracks are formed. Earthquakes often occur near these faults.
 

Divergent fault – When two plates are pulling away from each other. An example of this is seafloor spreading, where magma pushes through a crack in the crust at the mid-ocean ridge and forms new sea floor while pushing the continents apart.
Convergent fault – When two plates collide, pushing against each other.
Transform boundary – When two plates move alongside of each other.
 

Landforms:
Plains – low lying stretches of flat or gently rolling land.
Plateaus – flat lands that have higher elevation
Canyons – steep-sided lowlands that rivers have cut through a plateau
 

Bodies of Water
 

About 70% of the earth’s surface is water.
 

The five major oceans are The Atlantic, Pacific, Indian, Arctic and Southern Oceans
 

Almost 98% of the world’s water is salt water contained in the oceans. The remaining 2% is freshwater.
 

80% of the worlds freshwater is frozen in glaciers (giant sheets of ice located on land.)
Most of the remaining freshwater is groundwater. There is over 10 times as much groundwater as there is water in rivers and lakes.
 

Aquifer – underground rock layers that groundwater flows through.
 

Climate – the usual, predictable pattern of weather in an area over a long period of time.
 

The Tropics – areas near the Equator that lie between the Tropic of Cancer and the Tropic of Capricorn. These areas are warm because they receive the most direct angle of the suns rays.
 

Altitude (Elevation) also affects temperature. The temperature drops as you go to a higher elevation.

Greenhouse gases (carbon dioxide – CO2 and water vapor) prevent some of the earths heat energy from escaping into space. An increase in these gases will cause the overall temperature of the earth to rise.
 

Cutting down forests can cause less rainfall due to less evaporation from leaves and branches.