Transcript Ch 3, part 1

Chapter 3
Section 1
The Earth as a System

The earth is an integrated
system that consists of rock,
air, water, and living things
that all interact with each
other.

Scientists have divided this
system into four parts, the
geosphere, atmosphere,
hydrosphere, and biosphere.
Geosphere
 The
solid part of the
Earth that consists of
all rock, and the soils
and sediments on
Earth’s surface is the
geosphere.
 Most
of the
geosphere is located
in Earth’s interior.
Atmosphere


The atmosphere is
the mixture of
gases that makes
up the air we
breathe.
Nearly all of these
gases are found in
the first 30 km
above the Earth’s
surface.
Nitrogen
78.084%
Oxygen
20.946%
Argon
0.934%
Carbon dioxide
0.038%
Water vapor
Less than
1%
Other
0.002%
Hydrosphere

The hydrosphere makes
up all of the water on or
near the Earth’s surface.

Much of this water is in
the oceans, which cover
nearly ¾ of the Earth.
Biosphere
 The
biosphere is made up of parts of
the geosphere, atmosphere and the
hydrosphere.
 The
biosphere is the part of the Earth
where life exists.
The Composition of the Earth

Scientists divide the Earth
into three layers; the crust,
mantle, and the core.

The crust is Earth’s thin outer
layer and makes up less than
1% of the planet’s mass.

The mantle is the layer
beneath the crust and makes
up 64% of the Earth’s mass.

The core is the innermost
layer and is composed of the
densest elements.
The Structure of the Earth

Earth’s outer layer is the lithosphere,
which is a cool, rigid layer that is 15 km to
300 km thick.

It includes the crust and uppermost part
of the mantle. It is divided into huge
pieces called tectonic plates.
Asthenosphere

The asthenosphere is the layer beneath
the lithosphere.

The asthenosphere is a plastic, solid layer
of the mantle made of rock that flows very
slowly and allow tectonic plates to move
on top of it.
Plate Tectonics

Tectonic plates glide across the
asthenosphere in much the same way as a
chunk of ice drifts across a pond.

Continents that are on tectonic plates
move along with them.

The major tectonic plates include the
Pacific, North American, South American,
African, Eurasian, and Antarctic plates.
Plate Boundaries

Plates may separate from one another,
collide with one another, or slip past one
another.

Enormous force is generated at tectonic
plate boundaries , where the crust is
pulled apart, is squeezed together, or is
constantly slipping.

The forces produced at the boundaries of
tectonic plates can cause mountains to
form, earthquakes to shake the crust, and
volcanoes to erupt.
Earthquakes

A fault is a break in the
Earth’s crust along which
blocks of the crust slide
relative to one another.

When rocks that are
under stress suddenly
break along a fault, a
series of ground
vibrations is set off.
These vibrations of the
Earth’s crust caused by
slippage along a fault are
known as earthquakes.
Where earthquakes have struck
The Richter Scale

The Richter scale is used by scientists to measure
the magnitude, or the amount of energy released
by an earthquake.

The smallest magnitude that can be felt is
approximately 2.0, and the largest magnitude
ever recorded is 9.5. Earthquakes can cause
severe damage after 7.0.

Each increase of magnitude by a whole number
indicates the release of 31.7 times more energy
than the whole number below it.
Volcanoes

A volcano is a
mountain built from
magma that rises
from the Earth’s
interior to the
surface.

Volcanoes are often
located near tectonic
plate boundaries.

Global Effects of Volcanic Eruption

Major volcanic eruptions
can change the Earth’s
climate for several years.

In large eruptions, clouds of
volcanic ash and sulfur-rich
gases may reach the upper
atmosphere.

As soon as the ash and
gases spread across the
planet, they can reduce the
amount of sunlight that
reaches Earth’s surface.
Erosion

The removal and transport
of surface material is called
erosion.

Wind erosion blows the soil
away, which is where the
plant’s roots are located.

Water erosion is caused by
both rivers and oceans.
Waves from ocean storms
can erode coastlines, and
over time, rivers can carve
deep gorges into the
landscape.