The Earth as a System

1
Chapter 3

• Section 1

2
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.

3
Geosphere

• The solid part of the Earth that consists of all
  rock, and the soils and sediments on Earths
  surface is the geosphere.
• Most of the geosphere is located in Earths
  interior.

4

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 Earths surface.

Nitrogen 78.084
Oxygen 20.946
Argon 0.934
Carbon dioxide 0.038
Water vapor Less than 1
Other 0.002
5
Hydrosphere

• The hydrosphere makes up all of the water on or
  near the Earths surface.
• Much of this water is in the oceans, which cover
  nearly ¾ of the Earth.

6
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.

7
The Composition of the Earth

• Scientists divide the Earth into three layers
  the crust, mantle, and the core.
• The crust is Earths thin outer layer and makes
  up less than 1 of the planets mass.
• The mantle is the layer beneath the crust and
  makes up 64 of the Earths mass.
• The core is the innermost layer and is composed
  of the densest elements.

8
The Structure of the Earth

• Earths 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.

9
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.

10
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.

11
(No Transcript)
12
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.

13

• The forces produced at the boundaries of tectonic
  plates can cause mountains to form, earthquakes
  to shake the crust, and volcanoes to erupt.

14
Earthquakes

• A fault is a break in the Earths 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 Earths crust
  caused by slippage along a fault are known as
  earthquakes.

• Where earthquakes have struck

15
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.

16
Volcanoes

• A volcano is a mountain built from magma that
  rises from the Earths interior to the surface.
• Volcanoes are often located near tectonic plate
  boundaries.

17
Global Effects of Volcanic Eruption

• Major volcanic eruptions can change the Earths
  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 Earths surface.

18
Erosion

• The removal and transport of surface material is
  called erosion.
• Wind erosion blows the soil away, which is where
  the plants 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.