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Unit 3: Earth
StructuresBy Table 4
How old is the Earth? Scientists believe the Earth is about 4,600
million years old because that’s the age of the oldest rocks ever to be found
There’s also some layers with a crystalline core. The crystalline core is a called a kraton
They look a lot like geodes
How are the layers of the Earth formed?
Layers of rocks are formed when sediment is laid down on top of each other
Then gravitational compression, the energy of impacting bodies, and radiation will partially melt them together
When this happens, the densest material will sink toward Earth's center, while the less dense stuff will rise up to the top
*Sediment is rock formed from consolidated clay
Another way… A change in tectonic plate (A scientific
theory that describes the large-scale motions of Earth's lithosphere) motion can cause those sedimentary layers to be brought up so we can see them today
FUN FACT
This isn’t photoshopped. These are the Rainbow Mountains
In China's Danxia Landform
Don’t believe me? Google it
ONE MORE WAY! When volcanoes erupt, the lava that
comes out can spread across broad areas, forming a layer of igneous rock
within the sedimentary layers. The mantle is the layer that lies directly
under the crust. It’s the thickest layer and it’s super hot
FUN FACT
Did you know that the Earth’s core temperature is about 7000 degrees Celsius?
Video http://youtube.com/watch?
v=Q9j1xGaxYzY
Speaking of Volcanoes… What is it exactly?
A volcano is a mountain or hill, typically conical, having a crater or vent through which lava, rock fragments, hot vapor, and gas are being or have been erupted from the earth's crust. There are 3 types of volcanos; Shield, Cinder, and Composite.
Types of Volcanoes
Where can you find a volcano?
Volcanoes are on just about every continent. The area with the most concentration of volcanoes is know as the Ring of Fire. The ring of fire is the border of the Pacific plate (pacific ocean)
How does a volcano work? Active volcanoes are volcanoes that are
erupting or showing signs of activity. When pressure builds up, eruptions occur. Gases and rock shoot up through the opening and spill over or fill the air with lava fragments. Lava is molten rock or magma that is on the earths surface.
Largest Volcanoes 1. Mount Mazama/Crater Lake, Oregon-Over
6,000 ago Mount Mazama erupted. Before the explosion the mountain was 12,000 feet high.
2. Mount Etna, Sicily-Although Mount Etna the highest active volcano in Europe
3. Mount Vesuvius, Italy-Vesuvius' eruption in 79 A.D Vesuvius covered the cities of Pompeii and Herculaneum, preserving them for generations to come.
In what ways do volcanoes reconstruct the environment?
Volcanoes change the environment a lot. The lava can add land to earth. If
the eruption is explosive it can destroy the land. The gasses add the green
house gasses which contribute to global warming.
A video about Volcanoes http://www.youtube.com/watch?v=BcFtp
WjZwlE
Erosion can also reconstruct the Earth’s surface
What is erosion? Erosion is the wearing away of the land by
forces such as water, wind, and ice. Erosion has helped to form many interesting features of the Earth's surface including mountain peaks, valleys, and coastlines.
What causes erosion? There are many different forces in nature
that cause erosion. Depending on the type of force, erosion can happen quickly or take thousands of years. The three main forces that cause erosion are water, wind, and ice.
Erosion by Water Water is the main
cause of erosion on Earth. Although water may not seem powerful at first, it is one of the most powerful forces on the planet.
Here are some of the ways that water causes erosion
• Rainfall - Rainfall can cause erosion both when the rain hits the surface of the Earth, called splash erosion, and when raindrops accumulate and flow like small streams
• Rivers - Rivers can create a significant amount of erosion over time. They break up particles along the river bottom and carry them downstream. One example of river erosion is the Grand Canyon which was formed by the Colorado River.
• Waves – Ocean waves can cause the coastline to erode. The shear energy and force of the waves causes pieces of rock and coastline to break off changing the coastline over time.
• Floods - Large floods can cause erosion to happen very quickly acting like powerful rivers.
Erosion by wind and glaciers
Wind
Wind is a major type of erosion, especially in dry areas. Wind can erode by picking up and carrying loose particles and dust away (called deflation). It can also erode when these flying particles strike the land and break off more particles (called abrasion).
Glaciers
Glaciers are giant rivers of ice that slowly move carving out valleys and shaping mountains.
Random Facts about Erosion The word erosion comes from
the Latin word "erosionem" which means "a gnawing away."
Scientists estimate that the Colorado River has been eroding the Grand Canyon for many millions of years.
Wind erosion can cause huge dust storms.
The fastest glacier ever moved over seven miles in three months.
Fossils in sedimentary rock are often uncovered by erosion.
Video http://www.youtube.com/watch?
v=R48zYr-S7v0
That’s all great but what would happen if the Earth equilibrium messed up?
First we need to know what equilibrium is…
Equilibrium is the state of which systems are in balance.
Planetary Equilibrium Temperature
Planetary equilibrium- Theoretical temperature that the planet would be at when considered simply as if it were a black body being heated only by its parent star.
The presence or absence of an atmosphere (and therefore any greenhouse effect) is not considered, and one treats the theoretical black body temperature as if it came from an idealized surface of the planet
Hydrostatic Equilibrium A fluid is said to be in hydrostatic
equilibrium when it is at rest, or when the flow velocity at each point is constant over time.
This occurs when external forces such as gravity are balanced by a pressure gradient force. For instance, the pressure gradient force prevents gravity from collapsing the Earth's atmosphere into a thin, dense shell, while gravity prevents the pressure gradient force from diffusing the atmosphere into space.
Radiative Equilibrium The condition where a steady state system
is in dynamic equilibrium, with equal incoming and outgoing radiative heat flux and negligible heat transfer by conduction and convection
The net change in the tropopause after temperatures readjust to radiative equilibrium in the stratosphere, is used to determine the radiative forcing, as part of an assessment of natural and anthropogenic climate change
What is the atmosphere composed of?
The common name given to the atmospheric gases used in breathing and photosynthesis is air. By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other trace gases.
How do large bodies of water form?
Large bodies can form in many ways
They can form during earthquakes, rainfall, melting ice, condensation, evaporation man-made structures and volcanoes
Large bodies of water formed by earthquakes
A river can be formed when an earthquake splits the tectonic plates in a subduction zone the resulting gap was filled with water
Large bodies of water formed by rainfall Craters made by volcanoes or
meteorites could be filled over time with massive amounts of rain
Large body of water formed by ice
The great lakes were carved out of the earth by ice during the last ice age and has since then filled up either from melting ice or rainfall
Large bodies of water formed by evaporation/condensation Hurricanes get there strength from
heated ocean water that evaporates it then drops all of the water
Large bodies of water that are man-made
Lake Powell is the second largest man-made body of water
Large bodies of water formed by Volcanoes
Volcanoes can form large bodies of water either by exploding and leaving a caldera or by erupting and cutting off a river, thereby creating a lake or an island with a lake or river