Earth Science is the study of the Earth's physical features, and how they change over time
A geologist is a person who studies Earth Science
The Earth
The Earth is made up of 4 parts: a very hot, dense, and hard inner core (which is composed of iron and nickel), a hot liquid outer core, a hot, but soft-solid layer called the mantle, and the thin, cooler outer layer, which we call the crust
Plate Tectonics The Earth's crust is broken or fragmented into between 9 and 12 pieces. It is like a broken plate that has been glued back together. These broken pieces of crust are called plates. Since the mantle is soft the plates can float and move. The study of how these plates move is called plate tectonics.
Earthquakes I
Between the Earth's plates are deep cracks called faults The plates sometimes slide against each other along these faults If two plates slide violently against each other then the result is an earthquake. An earthquake is a violent shaking of the Earth's crust caused by plates moving against each other. The place where an earthquake happens is called the epicenter. The point on the Earth's surface directly above the epicenter is called the focus.
Earthquakes II
A seismologist is a person who studies these earthquakes. They use an instrument called a seismograph to record the Earth's movements. A seismograph is basically a cylinder with paper on it. It has an ink needle that is attached to the paper. When the Earth moves the needle moves, making a line on the paper. The bigger the line?the stronger the ground movement. The strength of a ground movement (or earthquake) is measured on the Richter scale. This scale goes from 1-10 with 1 being the smallest and 10 being the biggest. A person usually can't feel an earthquake smaller than 3 on the Richter scale. The biggest earthquakes are usually around a 7, although a 9 hit Alaska in the 1960?s.
Constructive Processes I
A constructive process is how the Earth builds up land There are many different ways to build up the land. Earthquakes, volcanoes, and deposition are all examples of constructive processes
Constructive Processes II
Earthquakes can construct new land by pushing one plate on top of the other?this creates new mountains Volcanoes can erupt
?sending lava and ash into the air?this results in new land being formed. Deposition is also a constructive process. Many forces such as water and wind, can move the soil from one place to another, thus depositing it as new land. Deltas, dunes, and moraines are all created by deposition of soil/rock from another area.
Destructive Processes I
A destructive process is when the Earth tears down or loses land. Erosion, weathering, earthquakes, volcanoes, and glaciers are all examples of destructive processes
Destructive Processes II
Earthquakes can push plates under each other, causing land to sink and disappear Volcanoes can erupt causing their top and sides to be blown away Rivers and glaciers can erode the soil around them Rain and wind can move soil and rocks from one place to another Destructive Processes III
Weathering can break apart rocks There are two types of weathering: chemical and mechanical. Chemical weathering occurs when acid rain, lichens, or other organisms actually change the composition of the rock. Mechanical weathering happens when tree roots, ice, water, waves, and heat or cold cause the rock to break apart.
Destructive Processes IV
There are many other examples of destructive processes: tsunamis, tornadoes, fires, avalanches, and hurricanes just to name a few. Of course all of these use water or wind in some way.
Georgia I
Although Georgia has no volcanoes or glaciers, and very few earthquakes, there are still many examples of constructive and destructive forces here in the state. The Appalachian Mountains were formed millions of years ago, when the Atlantic Plate slid under the North American Plate and pushed up the land. The barrier islands along the coast were formed by wind, waves, rivers, and hurricanes moving soil and rocks from one area to another.
Georgia II
Cloudland Canyon, Providence Canyon, and Amicalola Falls are all Georgia state parks where water erosion has changed the land.
Technology I
Sometimes man tries to control these constructive and destructive forces. Dams and levees can be built to control flooding and the erosion of soil along streams Dams and levees can control erosion and flooding. They can also help to produce electricity, and store water for our drinking supply. Unfortunately, dams and levees can also have negative impacts. They can displace people and wildlife, change the environment, harm fish, and are very expensive to build.
Technology II
Other ways in which man tries to control constructive and destructive forces: Farmers can plant trees as windbreaks, terrace the land in steep areas, and use contour plowing to limit the amount of wind and water erosion on their farms. Beach nourishment/replenishment is when the government puts extra sand on the beach to replace sand that was washed away during a storm. Seawalls (large concrete walls along the ocean) can also be used to control erosion.
Additional Vocabulary I
Floodplain-an area outside the normal course of the river that floods and receives sediment from the river Drumlin-a long, oval shaped mound of debris (rock and soil) formed by a glacier Desert pavement-when the ground is hard like pavement, because the wind has blown away all of the sand and dirt
Additional Vocabulary II
Arches/Sea Arches-a natural arch where the rock on top is hard and doesn?t erode, but the rock below is soft and does wear away Headland-a point of land that juts (sticks) out into the ocean