Chapter 6 Earth Science and the Environment

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Chapter 6Earth Science and the Environment

• Objectives
• Explain the role of earth science in
  environmental science
• Explain how scientists believe the earth was
  formed
• Describe the structure of the earth
• Explain changes and movements of the earth

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Terms
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Earth Science

• Earth science involves the planet earth and the
  area surrounding it
• This includes the soil, water, and atmosphere

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Areas of Earth Science

• Geology
• Hydrology
• Oceanography
• Meteorology
• Astronomy

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The Earths Formation

• Formation of the earth began by accretion about
  4.5 billion years ago.
• At first, the earth was very hot
• The mass split into two large area northern and
  southern area (about 135 million years ago) this
  separation is known continental drift
• Later, about 100 million years ago, these split
  again, the northern area formed North America and
  Europe-Asia and the southern area formed South
  America and Africa

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Solar System

• A solar system is a group of objects in space
  held together by a sun.
• Our solar system is a part of the Milky Way
  Galaxy.
• A solar system is made of a sun, planets,
  asteroids, meteoroids, and comets.

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Planet Movement and the Environment

• Rotation
• Revolution

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Rotation

• Rotation is the turning of the earth on the axis.
• It makes one complete rotation every 24 hours-one
  day.
• Light and dark
• Living organisms adapt to the rotations.
• Plants, light is a time of growth and dark is a
  time of rest.

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Revolution

• Revolution is the movement of the earth in space
  around the sun.
• The earth makes a revolution or orbit every
  365.24 days-one year.
• Seasons of the year are based on the position of
  the earth in a revolution.
• Sunlight (day length) and temperature changes
  influence when plants and animal reproduce and
  grow.
• Equinox is when the sun is directly over the
  equator.
• Solstice is when the earths axis tilts at the
  greatest angle toward or away from the sun.
• The earths orbit is slightly oval-shaped. (147
  and 152 million km)

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Shape and Size

• The diameter of the earth between the poles is
  12,713.54 km.
• At the equator, the diameter is 12,756.32 km
• The circumference of the earth is 40,007 km at
  the poles and 40,074 km at the equator

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Earth Materials and the Environment

• The earth is made of solid, liquid, and gaseuos
  materials
• Solid materials form the lithosphere
• The liquids are predominantly water and form the
  hydrosphere
• Gases are predominantly in the atmosphere

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The Lithosphere

• The lithosphere has three major layers surface,
  mantle, and core
• The surface of the earth is crust with areas of
  water and land
• Shapes on the earths surface are landform
• The thickness of the crust varies from about 16
  km under the oceans to about 40 km under land
• The crust that is beneath the oceans is oceanic
  crust, while that on land is continental crust
• The point at which the surface of the water and
  land naturally meet is sea level

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Surface

• About 70 percent of the earths surface is
  covered with, most of this water is in oceans
• Ocean average 3,730 m deep, the deepest known
  part of any ocean is the Mariana Trench
  (southwest of Guam) in the Pacific ocean (11,033
  m)
• About 30 percent of the earths surface is land
• The highest land is on the continent of Asia
  (Mount Everest is 8,848 m)

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Mantle

• The mantle is the interior of the earth located
  between the crust and core
• It is divided into the upper mantle and lower
  mantle
• The mantle is about 2,900 km thick
• Temperatures ranging from 870 C in the upper
  mantle to 4,400 C in the lower mantle
• Silicon, aluminum, iron, and other minerals make
  up the mantle

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Core

• The core is the center of earth
• The core is divided into inner and outer layers
• The outer core is about 2,240 km thick and made
  of nickel and iron
• The temperature in the core ranges between
  4,400-7,000 C
• The existence and movement of the molten core are
  thought to produce the electromagnetic field

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The Hydrosphere

• The hydrosphere consists of all of the water on
  the earth, which includes liquid, frozen, and
  gaseous forms
• Water goes through the hydrologic cycle

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Ocean

• The largest is the Pacific Ocean, followed by the
  Atlantic Ocean and Indian Ocean
• Oceans contain smaller bodies of water known as
  seas, gulfs, and bays
• The oceans have a big influence on our environment

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Rivers and Lakes

• Rivers and lakes are formed when precipitation
  (rain and snow) is greater than the ground can
  absorb
• Water that is not absorbed into the ground is
  called runoff
• Streams near large areas of population or
  factories often serve as places to dispose of
  wastewater

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Ground Water

• Ground water is the water beneath the surface of
  the earth
• Ground water is found in spaces between rocks and
  soil particles
• Water may form aquifer, which is an underground
  stream or pool in sand or gravel layers

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Atmosphere

• Atmosphere is the air that surrounds the earth
• The contents of the air are invisible gases,
  water vapor, and particulate

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Gases in the Air

• The major gases in the air are nitrogen (N) and
  oxygen (O2)
• Other gases in air are argon (Ar), carbon dioxide
  (CO2), neon (Ne), helium (He), krypton (Kr),
  hydrogen (H), xenon (Xe), and ozone
• Ozone is a form of oxygen resulting when three
  atoms of oxygen combine (O3), it has a bluish
  color and an unusual in concentrations

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Moisture and Particulate in the Air

• Moisture in the air is humidity
• The amount of moisture in the air is always
  higher over areas of water than over the land
• Particulate is made of tiny suspended particles
  that are invisible unless many of them are
  crowded together

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Structure
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Water

• Water is a powerful force that changes the
  surface of the earth
• Water can break and dissolve
• El Nino is a major weather phenomenon in the
  Pacific Ocean that affects North America and
  other land areas

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Weathering

• Weathering is a chemical and physical process
  that changes solid rock into small particles
• Chemical weathering is when chemicals in the air
  or water react with the rock and cause some
  disintegration
• Physical weathering involves temperature changes,
  wind, water, and the activity of organisms

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Glacial Action

• Glacial are thick masses of snow and ice that
  move slowly over the land
• They often form on mountains and move downward
  through valleys toward a stream or ocean

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Wind

• Wind is air naturally moving horizontally across
  the surface of the earth
• The wind can exert powerful force in moving
  features on the earths surface
• Soil formed by wind-blown material is loess

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Plate Tectonics

• The plates ride or float on the upper mantle
• They are range in thickness 10 to 96 km
• Some plates overlap and slide on the top of each
  other
• Moving rock under or deep in the crust can cause
  waves that create earthquakes

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Earthquakes

• An earthquakes is the shaking of the ground
  caused by movement in large sections of the crust
• Earthquakes may occur on land or in oceans
• Earthquakes often produce aftershocks, which are
  smaller earthquakes

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Volcanoes

• A volcano is an opening in the earth through
  which ashes, steam, and lava are expelled
• Most of the heat to create a volcano occurs 24 or
  more km into the earths surface
• Wind currents in the atmosphere may carry dust,
  ash, gases, and other materials from volcanic
  eruptions long distances

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Volcanoes

• Devastation caused by the eruption of Kiluaea
  Volcano on the island of Hawaii

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Tsunamis

• An earthquake or a volcanic eruption in or near
  water can cause a tsunami
• A tsunami is a large wave of water that can reach
  far above sea level when it goes ashore on land
• Most tsunamis occur along the Pacific and
  Atlantic Oceans

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Planetary Winds

• Planetary winds are air movements that effect the
  entire planet
• These winds are caused by heat from the sun, the
  sun warms the air near the equator more than the
  air near the poles as trade wind

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Local Winds

• Local winds are sea and land breezes
• As land warms during the day, the air over it
  rises, cooler air from the oceans rushes into the
  land creating ocean and sea breezes
• During the night, the land cools more than ocean,
  this cause the air over the ocean to rise and
  reverse the breeze so that it moves from the land
  toward the ocean

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Tests

• Why do we have seasons? Distinguish between
  equinox and solstice
• Why is only 1 percent of the earths water
  readily available for use?
• What surface and internal movements occur on the
  earth? How do these change the environment?
• What movements occur in the atmosphere?