The Changing Earth

Chapter 2 Section 1 & 2

The Structure of the Earth

Geology: the study of the earth’s physical structure and history—is a relatively new science. It deals, however, with very ancient history of the earth.

The Earth’s Inner Structure

The earth is made of mostly of iron, nicked and rock. They are arranged in four layers;Crust: is a band of solid rock at the surface of the planet. It 25 to 30 miles thick beneath the continents & 5 to 10 miles in the oceans.Mantle: A soft layer of molten rock. It extends for 1,800 miles toward the center of the Earth.Magma: is molten rock, is created when the mantle melts.

Cont.Core: is the solid metallic center of the earth and is made up of iron and nickel, which are under tremendous pressure.

Outer core: 1,380 miles thick

Inner core: 760 miles radius

The Earth’s Interior

Earth is the only planet in our solar system capable of supporting many forms

of life.

Atmosphere: gases surrounding the earth; oxygen we breath, protects the earth from radiation, & provides weather.Lithosphere: some is located in the ocean & others are found huge landmasses called continents.

Hydrosphere: is made up of the water elements on the earth (oceans, seas, rivers, lakes, & rain)

Biosphere: the part of the earth where plants & animals live.

Continental Drift TheoryIn 1915, the German geologist and meteorologist Alfred Wegener first proposed the theory of continental drift, which states that parts of the Earth's crust slowly drift atop a liquid core. There was once a “supercontinent” on earth & he called it Pangaea. 180 million year ago, Pangaea began to break into separate continents. The fossil record supports and gives credence to the theories of continental drift and plate tectonics.

                       

      

Section 2: Bodies of Water

Ocean & seas: the ocean cover about 71 % of our planet.Even through there is only one ocean; it is divide in 4 main partsAtlantic OceanPacific OceanIndian OceanArtic Ocean

Ocean MotionThe salty water of the ocean circulates through three basic motions:CurrentsWavesTides The motion of the ocean helps distribute heat on the planet. Winds blows over the ocean & are either heated or cooled by the water. They then blow over land causes warmth or coolness.

Hydrologic cycleIs the continous circulation of water between the atmosphere, the ocean, & the earth.

Landforms on Earth’s Surface

Tectonic forces inside the Earth have produced four major types of landforms

Mountains & hills: Mts. tend to be more sparsely populated than hills and usually lie at 2,000 to 3,000 ft. above sea level. Ex: the Rocky Mts., Andes Mts., the Alps, Ural Mts. & the Himalayas. Hills are lower, rounded, and generally less steep than Mts.

Cont.Plains are relatively low-lying, level areas that in many cases are gently rolling. Largest plains in the world are the Central Plains of N. America, the Amazon Basin in S. America, North European Plains & flat plains of central Australia.Plateaus are relatively level like plains, but they located at higher elevations. They have at least one steep side where a line of cliffs, escarpment, separates the plateau from neighboring low-lying areas.

Landforms

                                                                 

Oceanic Lanforms

The seafloor has landform similar to those above water.It has ridges, valleys, canyons, plains & mountains chains similar to those on the continents.Islands are form by volcanic action, deposit of sand, or deposits of coral skeletons.Longest Mountains range is Mid-Atlantic Ridge.

Sonar