Download Chapter 2.1

Chapter 2.1
Earth: A Unique Plan
Earth: A Unique Planet
1)Earth
a)A unique planet in our solar system.
b)The only planet with liquid water on
its surface.
c)The only planet with an atmosphere
that contains a large amount of
oxygen.
d)The only planet know to support life.
The Earth’s Shape
1) The Earth’s Shape: A Sphere?
a) The Earth appears to be a perfect sphere, however
it is not.
i) The Earth is an oblate spheroid.
(1)The circumference around the poles is
40,007 km.
(2) circumference around the equator is 40,074
km.
ii)This shape is caused by the spinning of the
earth on its axis.
(1)The axis is an imaginary line that runs
from the north pole to the south pole.
Oblate Spheroid
Hydrosphere & Atmosphere
1) Hydrosphere & Atmosphere
a) All of the earth’s water makes up the hydrosphere
i) The earth is 71% covered by water.
(1)97% of that water is in the oceans
(2)3% of that water is in lakes , rivers,
streams, and ice sheets.
b)All of the gases that surround the earth makes up
the atmosphere.
i) The atmosphere is 78% nitrogen, 21% oxygen,
and 1% other gases such as argon, carbon
dioxide, and helium.
The Earth’s Interior
1) The Earth’s Interior
a) The earth’s interior is made up of three major
zones: the crust, mantle, and core.
b)The Earth’s Crust
i) The crust is the outermost zone of the earth.
ii)It is a thin and solid and makes up only 1% of
the earth’s mass.
iii)Oceanic crust is found beneath the oceans and
is only 5 km to 10 km thick.
iv)Continental crust makes up the continents and
is 15 km to 80 km thick.
The Earth’s Interior
a)The Earth’s Mantel
i)This zone of rock is 2,900 km thick.
ii)Makes up 2/3 of the earth’s mass.
iii)It is broken up into two sections:
the lithosphere and the
asthenosphere.
Earth’s Interior
Lithosphere & Asthenosphere
(1)The lithosphere
(a) The cool, rigid, brittle, upper portion of
the earth’s crust.
(b)It is 15 km to 300 km thick.
(2)Asthenosphere
(a)An extremely hot layer of the mantel
that is under an enormous amount of
pressure.
(b)Due to the enormous amount of heat
and pressure, the solid rock of the
asthenosphere has the ability to flow.
This is called plasticity.
Lithosphere & Asthenosphere
The Earth’s Core
a) The Earth’s Core
i) This section is the center of the earth and is made
mostly of iron.
ii)The core makes up 1/3 of the earth’s mass.
iii)The core is also broke into two sections: the outer
core and the inner core.
(1)The outer core
(a)Scientists believe the outer core is a dense
liquid layer about 2,250 km thick.
(2)The inner core
(a)Scientists believe the inner core is a dense,
solid sphere with a radius of 1,228 km.
Seismic Waves
1) Seismic Waves
a)A form of a wave (energy) that scientists use
to study the earth’s interior.
b)There are two forms of waves that scientists
use to study the earth’s interior, they are P
waves or primary waves and S waves or
secondary waves.
c)P waves travel through liquids, solids, and
gases while S waves only travel through
solids.
Seismic Waves
a)Primary waves travel faster than
secondary waves.
b)Scientists can use these waves to study
the earth’s interior because the speed
and direction of both types of waves
are affected by the composition of the
material they travel through. The
more rigid the material the faster the
waves travel.
Andrija Mohorovicic
1) Andrija Mohorovicic
a) Performed a seismic wave study in 1909 that
showed the boundaries of the zones in the earth’s
interior.
b)Mohorovicic discovered that the speed of the
seismic waves increased at the boundary from the
crust to the mantel.
i) This boundary is called the Mohorovicic
discontinuity, or the Moho.
ii)This also indicates the earth’s mantle is denser
than the crust.
Andrija Mohorovicic
a)Changes in P wave and S wave speed
occur at the boundary of each zone of
the earth’s interior. The S-waves also
appear to disappear at the earth’s
outer core due to its liquid like
properties, and the P-waves slow
down for the outer core but speed up
for the inner core.
Shadow Zones
a)Shadow zones are areas in the earth
where P and S waves do not travel or
only P waves travel.
i)This absence of waves is caused by a
change in uniform rigidity. Meaning
its ability to resist deformation is
different throughout the area of the
earth.
ii)Shadow zones can be caused by the
makeup of the substance and
earthquakes.
P & S Waves
The Earth’s Magnetic Field
1) The Earth’s Magnetic Field
a)Along with the north and south pole, the
earth also has magnetic poles.
i)The poles are called the north
geomagnetic pole and the south
geomagnetic pole.
b)The magnetosphere is a region of space
beyond the earth’s atmosphere that is
affected by the earth’s magnetic field.
Geomagnetic Poles
The Earth’s Magnetic Field
a)Scientists believe that the motion within the
earth’s outer core creates our magnetic field
because it is mostly iron which is a good
conductor. However, scientists also know
that the sun and moon have magnetic fields
but the sun contains little iron and the
moon doesn’t have a liquid core.
b)The exact source of the earth’s magnetic
field has yet to be proven.
Earth’s Magnetic Field
The Earth’s Gravity
1)The Earth’s Gravity
a)Gravity is the force of attraction that
exists between all matter in the
universe.
b)Originally studied and by Sir Isaac
Newton who describe the effect of
gravity through his law of gravitation.
The Earth’s Gravity
a)This law states that the force of
attraction between any two objects
depends upon their masses and the
distance between them.
i)The larger the mass and the shorter
the distance between two objects the
greater the gravitational attraction
they have between themselves.
Weight & Mass
a)Weight and mass are not the same.
i)Mass is the amount of matter in an
object and is measured in kilograms (kg).
ii)Weight is the force of gravity on that
matter and is measured in newton’s (N).
(1)The weight of an object depends on
its mass and distance from the earth’s
center.
Weight & Mass
Weight & Mass
(1)The closer to earth’s center the heavier the
object will become and the further away
from the earth’s center the lighter the object
will become.
(2)At the earth’s surface a 1 kg mass weighs
about 10 N and 19,778 km from the earth’s
core a 1 kg mass now weighs 1 N.
(3)Due to the oblate spheroid shape of the
earth, your weight at the equator is about
.3% less than your weight at the north pole.
Weight, Mass, & Distance