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Chapter 3
The dynamic Earth
Earth as a system
a system is a set of particles
or interacting components
considered to be a distinct
physical entity for the purpose
of study

Parts of the system
Geosphere
Hydrosphere
Atmosphere
Biosphere
Composition of the Earth
 Crust-
made of light elements, less
than 1% of the Earth’s mass, thinnest
layer
 Two kinds- oceanic(thin and dense)
and continental (thick and less dense)
Mantle-
made of dense
Iron rich minerals, makes
up most of the mass of the
Earth (64%)
Core-
densest, inner most layer,
made of Iron and Nickel
containing minerals, makes up
about 35% of the Earth’s mass
Five physical layers
 Lithosphere
– the cool, rigid, outermost layer
of the Earth; consists of the crust and the
uppermost part of the mantle; divided into
huge pieces called tectonic plates
 Asthenosphere
– the solid, plastic layer
of the mantle between the mesosphere
and the lithosphere, made of mantle rock
that flows very slowly, which allows the
tectonic plates to move on top of it
Mesosphere
– the lower layer of
the mantle between the
Asthenosphere and the outer core;
known as the “middle sphere”
Outer
Core – the outer shell
of Earth’s core; made of liquid
nickel and iron
Inner
Core – a sphere of
solid nickel and iron at the
center of the Earth
How do we know about the
inside of the earth?
Theory of plate tectonics

Alfred
Wegener’s
Hypothesis
The
Supercontinent
Cycle
Tectonic plates
The
main features of plate
tectonics are: 1. The Earth’s
surface is covered by a series of
crustal plates.
2.
The ocean floors are
continually, moving, spreading
from the center, sinking at the
edges, and being regenerated.
3.
Convection currents beneath
the plates move the crustal
plates in different directions.
The
source of heat driving
the convection currents is
radioactivity deep in the
Earth’s mantle.
Types of plate boundaries
Plates
move
apart
Plates collide- whichever is
more dense is subducted(sinks
and melts)- Same density=
mountians formed(Himalayas)
Plates slide past each other
CLE 3260.1.2 Use the theory of
plate tectonics to explain the
occurrence of earthquakes,
volcanoes, and tsunamis.
 An
earthquake is the vibration caused
when there is movement along a
fault
 elastic rebound the sudden return of
elastically deformed rock to its
undeformed shape
 fault
(the place where the ground actually
breaks apart)
 Occur
at or near tectonic plates boundaries
Types of earthquake waves
 body
wave a seismic wave that
travels through the body of a
medium
 surface wave a seismic wave that
travels along the surface of a
medium and that has a stronger effect
near the surface of the medium
 Each
type of wave travels at a
different speed and causes different
movements in Earth’s crust.
Types of body waves
P
waves- Primary or
compression wavestravel as a region of
compression- move
particles together and apart
P
waves are the fastest seismic
waves
 The more rigid the material is, the
faster the P wave travels through it.
S
waves- shear waves- slower
than primary- travel like a vibration
through jello- move particles up
and down
 S waves are the second-fastest
seismic waves
 surface
waves- cause most of
the damage during an
earthquake- the slowest
wave
 Love
waves are surface waves
that cause rock to move side-toside and perpendicular to the
direction of the wave.
 Rayleigh
waves are surface
waves cause the ground to move
with an elliptical, rolling motion.
Group activity
 With
one partner
 Take the slinky I will give you.
 Watch me simulate the movements
of body waves
 You try it
 Try to simulate the remaining types
of body and surface waves
movements
 Now,
try to do all the movements
together.
 Think about these questions:
 If you were to rank the types of
seismic waves in order from most to
least destructive, what how would
you organize them?
 How can people protect themselves
from the effects of earthquakes?
 Why are earthquakes sometimes in
places that are not near a plate
boundary?
The
focus is the spot
below the surface of the
earth where the earthquake
starts
The epicenter is the spot
on the surface of the earth
above the focus
Exit ticket questions
 1.
 a.
 b.
 c.
 d.
The fastest type of earthquake wave is a(n)
l wave
e wave
s wave
p wave
 2.
The type of earthquake wave that does the
most damage in an earthquake is the
 a. p wave
 b. s wave
 c. e wave
 d. surface wave
 3.
Which of the following is the most
geologically active region on the surface of
Earth?
 a. glacial valleys
 b. boundaries between tectonic plates
 c. recharge zones
 d. mountain peaks
 The
study of earthquakes and
seismic waves is called seismology.
 The motion generated by this movement
is detected by a seismograph

seismogram a tracing of earthquake
motion that is recorded by a seismograph
Volcanoes
 The
quantity of the amount of energy
released by an earthquake is measured by
the Richter scale
 The measure of the energy released by an
earthquake is called magnitude
Volcanic Formation
Under
the earth,
there are extreme
temperatures &
pressure
Magma-
liquid hot rocks
that are
underground(upper
mantle)
Magma may come up to
the surface through cracks
or by melting surrounding
rock
When
magma
reaches the
surface it is called
lava
Lava
may form a cone shaped
mountain
Lava erupts through an opening
called a vent
Volcanic Eruptions
 May
be violent or slow
 Rock fragments are blown up
 The smallest volcanic dust
 volcanic ash
 Lapilli Large particles, volcanic bombs
 Largest- volcanic blocks
There are 3 Types
of Volcanoes
Shield
Volcanoes
Formed
from quiet
lava flows
Has
a
gentle
slope
Cinder
Cones
Formed
from
explosive
eruptions
Have
a
narrow base
& steep
sides
Composite
Volcanoes
 Formed
by
alternating
layers of rock
particles
 Formed by
alternating
violent & quiet
eruptions
Volcanoes
may be classified
as
Active- a volcano that has
had at least one eruption
during the past 10,000 years.
Dormant-an active volcano
that is not erupting, but
supposed to erupt again.
Extinct-has
not had
an eruption for at
least 10,000 years
and is not expected to
erupt again in a
comparable time
scale of the future.
Volcanoes
 Large
scale volcanic eruptions can
affect global climate by reducing
the amount of sunlight that
reaches the Earth by 2-4%.
 This can cause average global
temperatures to drop by several
tenths of a degree Celsius for
several years
Tsunamis
 tsunami
a giant ocean wave that
forms after a volcanic eruption,
submarine earthquake, or landslide
Tsunamis
Wind and Water
 Wind
and water change the surface
of the Earth because of erosion
 The landscape is changed as rock is
broken down and carried away.
 Sediments can also be deposited in
other areas.
Ch 3 Section 2
Atmosphere
 78%
nitrogen-from volcanoes
and organic decay
 21% oxygen-given off by
plants
 1% mixture of gases such as:
argon, carbon dioxide, methane
water vapor, atmospheric dust
Layers of the atmosphere
 Troposphere-
closest to Earth,
densest layer, almost all weather
occurs here, temperature decreases
as altitude increases.
 Stratosphere-
temperature rises as
altitude increases because of ozone,
ozone absorbs UV light,
protecting living things from
damage to cells
http://earthguide.ucsd.
edu/earthguide/diagram
s/atmosphere/index.ht
ml
 Mesosphere-
above stratosphere,
coldest layer of the atmosphere
 Thermosphere-farthest
from the
Earth, very hot, but you wouldn’t feel it
because the molecules are so far apart,
nitrogen and oxygen absorb x-rays and
gamma rays, the lower thermosphere is
called the ionosphere, this is where the
aurora borealis and australialis are.
Heat transfer
Radiation-
moves
heat through space in
waves, to heat the
Earth’s surface
Conduction
Flow
of heat from a
warmer object to a
colder object when
they are in direct
physical contact
Convection
Transfer
of heat by
air currents, hot air
rises, cold air sinks
Also in liquids
Greenhouse effect
 Gases
in the atmosphere trap
heat to the Earth’s surface.
 Without the greenhouse effect,
the Earth would be too cold to
support life.
 Gases include carbon dioxide, water
vapor, methane, ozone
Section 3 Water cycle
Evaporation
Condensation
Precipitation
The Earth’s Oceans
Antarctic
Ocean
Arctic Ocean
Atlantic Ocean
Indian Ocean
Pacific Ocean
Temperature zones of the ocean
Surface
zone- warm top layer
of the ocean
Thermocline- temperature
drops rapidly with increased
depth
Deep zone- extends to
bottom of the ocean, avg.
temp is about 2degrees C
Ocean Currents
Surface
currents- wind
driven, result from global
wind pattern
Deep currents- cold water at
the poles sinks and moves to
equator along the ocean
floor, slower moving
Regulate temperature
Absorbing
and
storing energy from
the sun
Oceans regulate
global climate
biosphere
Liquid
water
Livable temperature
range
Source of energy
Systems
 Closed
system- energy enters,
but matter does not
 Open system- both matter and
energy are exchanged between a
system and the surrounding
environments
.