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Chapter 3: The Dynamic Earth. Environmental Science Class Mrs. Toner. Essential Question for this Lesson. How is the Earth a system of interacting components?. www.nasa.gov. Section 1: The Geosphere.
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Chapter 3: The Dynamic Earth Environmental Science Class Mrs. Toner
Essential Question for this Lesson • How is the Earth a system of interacting components? www.nasa.gov
Section 1: The Geosphere • http://photos.travelblog.org/Photos/83584/362141/t/3325183-Lava-flow-down-the-volcano-2.jpg • http://4.bp.blogspot.com/_Gyn0-PcXrJY/SpeZc7IviQI/AAAAAAAAAjI/W0W2qhkNx4s/S668/volcanoUPI_468x311.jpg • http://i.treehugger.com/images/2007/10/24/hurricane-jj-001.jpg
The Geosphere (cont.) • What are the conditions that allow us to survive on a constantly changing planet?
Earth as a System • The Earth consists of four parts that all interact with each other: • Rock (Geosphere) • Air (Atmosphere) • Water (Hydrosphere) • Living Things (Biosphere)
Earth as a System: The Geosphere • The solid part of the Earth that consists of all rock, as well as the soil and loose rocks on Earth’s surface is the geosphere. • Most of the geosphere is located in Earth’s interior. http://www.isws.illinois.edu/nitro/images/biggraph.jpg
The Geosphere http://www.salemstate.edu/~lhanson/gls100/image1/Internal_layersUSGS.gif
Earth as a System (cont.) • The atmosphere is the mixture of gasses that makes up the air we breathe. • Nearly all of these gases are found in the first 30 km above the Earth’s surface. http://csep10.phys.utk.edu/astr161/lect/earth/atmosphere.gif
Earth as a System (cont.) • The hydrosphere makes up all of the water on or near Earth’s surface. • Much of this water is in the oceans. • Water is also found in the atmosphere, on land, and in the soil.
Hydrosphere http://www.uwsp.edu/geo/faculty/ritter/images/hydrosphere/hydrocyc.jpg
Earth as a System (cont.) The biosphere is made up of parts of the atmosphere, the geosphere, and the hydrosphere. It is where life exists. http://www.uwsp.edu/geo/faculty/ritter/images/hydrosphere/hydrocyc.jpg
Earth’s Interior • The Earth is made up of three different compositional layers: • Crust (least dense) • Earth’s thinnest outer layer, makes up less than 1% of Earth’s mass. • Mantle (medium density) • Layer beneath the crust, makes up 64% of Earth’s mass. • Core (most dense) • Earth’s innermost layer, • Made up of hot nickel and iron at the center of the Earth
Structure of the Earth • If we consider the physical properties of each layer of Earth, then Earth can be divided into five physical layers: • Lithosphere – Earth’s outer layer • Includes the crust and uppermost part of the mantle • It is a cool, rigid layer • 15-300 Km thick • It is divided into huge pieces called tectonic plates. • Asthenosphere – Layer beneath the lithosphere • A plastic , solid layer of the mantle made of rock that flows very slowly to allow the tectonic plates to move on top of it.
Structure of Earth (continued) • Mesosphere • Beneath the asthenosphere • The lowest part of the mantle • Outer Core • A dense liquid layer • Inner Core • Dense, solid • Iron and nickel • HOT – 4,000 to 5,000 degrees Celsius! • It is solid because it is under enormous pressure
Compositional Layers Physical Layers
Annenberg Media: Earth Revealed Video • http://www.learner.org/resources/series78.html?pop=yes&pid=317#
Activity – work individually • On plain white paper • Horizontal orientation • Divide the paper into two sections • On the left side - draw, label and color the compositional layers of Earth. • On the right side – draw, label, and color the physical layers of Earth. • List three facts for each layer. • Use page 65 in the text as a reference. • Worth 35 points!
Plate Tectonics • The lithosphere is divided into pieces called tectonic plates. • These plates glide across the underlying asthenosphere. • The continents are located on tectonic plates. • Major plates: • Pacific Plate • North American Plate • South American Plate • African Plate • Eurasian Plate • Antarctic Plate
Plate Tectonic Animations • http://www.classzone.com/books/earth_science/terc/content/visualizations/es0804/es0804page01.cfm?chapter_no=08 • http://www.pbs.org/wgbh/aso/tryit/tectonics/#
Plate Boundaries • Plate boundaries are the boundaries between tectonic plates. • Divergent Boundaries - plates move away from one another (seafloor spreading) • Convergent Boundaries - plates collide into one another (mountains, volcanoes, earthquakes) • Transform Boundaries - plates slip past one another (earthquakes like the ones in California at the San Andreas Fault)
SECTION 2: THE ATMOSPHERE Chapter 3, Pages 71-76
Section 2: The Atmosphere • Earth is surrounded by a mixture of gases known as the atmosphere. • Nitrogen (N2) • Oxygen (O2) • Carbon Dioxide (C02) • Earth’s atmosphere changes constantly as these gases are added and removed. • As animals and humans breathe in, oxygen is removed from the atmosphere. As animals and humans breathe out, carbon dioxide is added. • Plants absorb carbon dioxide from the atmosphere and release oxygen into the atmosphere during photosynthesis.
The Atmosphere (Cont.) • The atmosphere also insulates Earth’s surface. • It keeps Earth at temperatures at which living things can survive.
Composition of the Atmosphere • 1. Nitrogen= 78% of the atmosphere • It enters the atmosphere when volcanoes erupt, and when dead plants and animals decay. • 2. Oxygen= 21% • Is primarily produced by plants. • 3. Other Gases = 1% • Methane • Carbon dioxide • Argon • Water vapor
Air Pressure • Earth’s atmosphere is pulled towards Earth’s surface by gravity. • As a result of gravity, the atmosphere is denser at Earth’s surface. • The air becomes less dense as elevation increases, so breathing at higher elevations is more difficult.
Layers of the Atmosphere • 1. The Troposphere : • Extends to about 18 Km (10 miles) above Earth’s surface • It’s where we live and where weather occurs. • Densest layer of atmosphere • Temperature decreases as altitude increases in the troposphere.
2. The Stratosphere • Above the troposphere • Extends 18-50 Km (or 10-30 miles) above Earth’s surface) • Where airplanes fly • Where ozone layer is • Temperature increases as altitude increases because ozone in the stratosphere absorbs the Sun’s UV energy and warms the air.
3. The Mesosphere • The layer above the stratosphere. • Extends to an altitude of about 80 Km (48 miles). • The coldest layer of the atmosphere (- 60 to - 90 degrees Celsius).
4. The Thermosphere • Atmospheric layer farthest from Earth’s surface. • The air is very thin in this layer so it is the least dense of all the layers. • Nitrogen and oxygen atoms absorb x-rays and gamma rays emitted from the Sun making them electrically charged. This causes the Northern Lights over the North and South Poles.
CBS Video: “To the Edge of Earth and Back” • http://www.cbsnews.com/video/watch/?id=5722794n
Energy in the Atmosphere • Energy from the Sun is transferred in Earth’s atmosphere by three mechanisms: • 1. Radiation • 2. Convection • 3. Conduction
1. Radiation • Radiation is the transfer of energy across space and in the atmosphere. • When you stand before a fire, the heat you feel has reached you by radiation. • See diagram on next slide.
2. Conduction • Conduction is the flow of heat from a warmer object to a colder object when the objects are placed in direct physical contact. • Like when you touch the handle of a hot pot.
3. Convection • Convection is the transfer of heat by air currents. • Hot air rises and cold air sinks. • If you were to hold your hand above a hot iron, you would feel the heat because a current of hot air rises up to your hand. • See diagram on next slide.
Energy Transfer Interactive • http://www.wisc-online.com/Objects/ViewObject.aspx?ID=SCE304
The Greenhouse Effect • Is the process in which gases trap heat near the Earth. • 1. Sunlight that penetrates Earth’s atmosphere heats the surface of the Earth. • 2. Earth’s surface radiates heat back to the atmosphere where some of the heat escapes back into space. • 3. The remainder of the heat is absorbed by greenhouse gases (carbon dioxide and water vapor), which warms the air and the surface of the Earth.