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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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:
1. Lithosphere – Earth’s outer layer
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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.
2. Asthenosphere – Layer beneath the lithosphere
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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)
3. Mesosphere
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Beneath the asthenosphere
The lowest part of the mantle
4. Outer Core
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A dense liquid layer
5. Inner Core
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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.ht
ml?pop=yes&pid=317#
Activity – work individually
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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:
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Pacific Plate
North American Plate
South American Plate
African Plate
Eurasian Plate
Antarctic Plate
Tectonic Plate Map
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.
Atmospheric Gas Exchange
Example
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%
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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.
The Northern Lights
More Northern Lights
CBS Video: “To the Edge of Earth
and Back”
• http://www.cbsnews.com/video/watch/?id=5
722794n
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.wisconline.com/Objects/ViewObject.aspx?ID=SCE
304
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.