Chapter 2

A Living Planet

Section 1

The Earth Inside and Out

Solar System

Continents- Land masses above water on earth. They fit together like a jigsaw puzzle. (Example: South America-Africa.

Solar System- Consist of the Sun and nine know planets. The earth is the 3rd planet from the sun.

The Structure of Earth: Inside the Earth

Core-is the solid metallic center of the earth and is made up of iron and nickel under tremendous pressure.

Mantle-a soft layer of molten rock about 1,800 miles thick.

Magma-molten rock created when the mantle melts the under side of the crust.

Crust-the then layer of rock on the earths surface.

The Structure of The Earth:On and Above the Earth

Atmosphere-a layer of gases surrounding the earth. Contains oxygen we breath and protects the earth from space debris. Helps control the climate.

Lithosphere-The solid rock portion of the earths surface. Some of the lithosphere is below water and forms the ocean floor.

Hydrosphere-Water elements on the earth. (lakes, oceans, rivers, and seas).

Biosphere-all three spheres combined to form the place where plants and animals live.

Continental Drift

Continental Drift- A theory that states all of the continents used to be connected and were a super continent called Pangaea.

Section 2

Bodies of Water and Landforms

Bodies of Water

Oceans and Seas- The ocean is an interconnected body of salt water that covers 71% of the earth. Geographers divide the ocean into 4 parts; Atlantic, Pacific, Indian, and Artic Ocean.

Ocean Motion-Ocean water circulates through TIDES, WAVES, and CURRENTS.

The circulation of the ocean helps distribute heat on the planet. Winds blow over the ocean and are either heated or cooled.

Bodies of Water

Hydrologic Cycle -Continuous circulation of water between atmosphere, oceans, and the earth.

Lakes, Rivers, and Streams- Lakes hold more that 95% of the earths fresh water supply. A drainage basin is an area drained by a river and its tributaries. Salt water lakes are formed when rivers deposit salt and there is not out flow of water.

Bodies of Water

Ground Water- Water held in pores of rock. The level at which the water is saturated marks the rim of the Water Table.

Landforms

Oceanic Landforms- The earth’s surface from the edge of a continent to the deepest part of the ocean floor is known as the Continental Shelf. Many features found on the earth’s surface are also found on the ocean floor.

Continental Landforms- Relief is the difference in elevation between the highest point and lowest point of a land form. There are four categories of relief; mountains, hills, plains, and plateaus.

Landforms

Topography-is the combination of the surface shape composition of the landforms and their distribution in a region. Topographic map shows landforms with their vertical dimensions and their relationship to other landforms.

Section 3

Internal Forces Shaping The Earth

Plate Tectonics

Internal forces that shape the earth begin immediately under the earths crust. Magma beneath the earth circulates constantly. Tectonic plates ride above the circulation of magma.

Tectonic Plates-Enormous moving pieces of land that form the earth’s crust

Tectonic Plates Cont.

Tectonic Plates move in four ways.

1. Spreading-moving apart

2. Subduction-diving under another plate

3. Collision-crashing into another plate

4. Sliding-shear one another as they pass

Tectonic Plates Cont.

Divergent boundaries-Plates move apart or spread.

Convergent boundaries-Plates collide Transform boundaries-Plates slide past one

another.

Tectonic Plates Cont.

Folds- some rock becomes more flexible under pressure and as the plates move. This creates slow changes in the earths crust.

Faults-Some rocks are so hard that they can not become flexible so they fracture under pressure this is called a fault. A fault line is the place where the plates move against one another.

Earthquakes

Earthquakes- are violent movements that occur when plates grind against each other at a fault.

Seismograph-is a special devise that helps scientist detect earth quakes.

Focus-Is the location on earth where an earthquake begins.

Epicenter-Is the location directly above the focus.

Earthquake Damage

Earthquakes can cause severe damage. Including landslides, fires (ruptured gas lines), and collapsed buildings.

Richter Scale-Uses information from seismographs to determine the intensity of an earthquake.

Tsunami-Is a large wave generated by an earthquake that spreads out from the epicenter. Waves can travel 450 MPH. Generally waves reach 50-100 feet. The record wave is 238 ft.(20 stories) in Japan.

Volcanoes

Magma, gases, and water from the lower crust or parts of the mantle collect in chambers. Eventually enough pressure builds and the lava, gas, and water explode from the earths crust. A volcano is a crack in the earths surface where the materials pour out.

Lava-is magma that reaches the earth’s surface.

Volcanoes Cont.

Volcano eruptions are very unpredictable. A volcano can remain inactive for hundreds of years before becoming active again.

Ring of Fire-A zone around the rim of the Pacific Ocean where most of the worlds active volcanoes exist.

Sect. 4 External Forces Shaping the Earth

Weathering-refers to the physical and chemical processes that change the characteristics of rock on or near the earths surface.

Sediment-is smaller and smaller pieces of rock created by weathering. Usually sand, mud, or silt.

Weathering

Mechanical Weathering-A process that breaks rock into smaller pieces. Examples Ice crystals and plant roots can form in the cracks of rocks and eventually break them apart.

Chemical Weathering - occurs when rock is changed into a new substance as the result of interaction between elements in water, air, and the rocks. Examples: Cave formations, Iron rusting, and Acid Rain.

Erosion

Erosion-occurs when weathered material is moved by water, wind, ice, or gravity.

Water erosion- occurs as water carries particles down stream. Abrasion from the particles eat away the rock forming the river bed.

Deltas-a fan shaped landform resulting from the deposit of silt at the mouth of rivers.

Erosion

Wind Erosion-When wind speeds reach 11 miles per hour, the wind carries sediments and deposits them in different locations.

Loess-are deposits of wind blown sediment that produce very fertile soils.

Glacier Erosion

Glacier- is a large, long lasting mass of ice that moves due to gravity.

Glaciation-is the changing of landforms due to the movement of glaciers.

Moraine-ridges and hills left behind from moving glaciers.

U shaped V shaped

Building Soil

Humus-organic material is soil.

Soil factors Parent Material-Chemical composition of the

parent rock. Relief-Steeper slopes are eroded quickly and

do not produce soil quickly. Organisms-small animals, plants, and

bacteria that help loosen the soil and provide nutrients.

Soil Factors Cont.

Climate-Climate plays a huge factor in soil production.

Time-the amount of time it takes to make soil varies.