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Volcanoes and Igneous Activity Earth - Chapter 4

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					Earth Science,
     12e
 Introduction to
  Earth Science
    Chapter 1
             Earth Science
vEncompasses all sciences that seek to
 understand
  • Earth
  • Earth’s neighbors in space
vEarth Science includes
  • Geology – literally the “study of Earth”
  • Oceanography – a study of the ocean
            Earth Science
vEarth Science includes
  • Meteorology – the study of the atmosphere
    and the processes that produce weather
  • Astronomy – the study of the universe
People and the environment

vEnvironment
  • Surrounds and influences organisms
  • Physical environment encompasses water,
    air, soil, and rock
  • Term “environmental” is usually reserved
    for those aspects that focus on the
    relationships between people and the
    natural environment
People and the environment

vResources
 • An important focus of the Earth sciences
 • Includes water, soil, minerals, and energy
 • Two broad categories
   • Renewable – can be replenished (examples
     include plants and energy from water and wind)
   • Nonrenewable – metals (examples include
     metals and fuels)
People and the environment

vPopulation
  • Population of the planet is growing rapidly
  • Rate of mineral and energy usage has
    climbed more rapidly than the overall
    growth of population
vEnvironmental problems
  • Local, regional, and global
People and the environment

vEnvironmental problems
  • Human-induced and accentuated
    •   Urban air pollution
    •   Acid rain
    •   Ozone depletion
    •   Global warming
  • Natural hazards
    • Earthquakes
    • Landslides
People and the environment

vEnvironmental problems
  • Natural hazards continued
    • Floods
    • Hurricanes
  • World population pressures
        Scientific inquiry

vScience assumes the natural world is
  • Consistent
  • Predictable
vGoal of science
  • To discover patterns in nature
  • To use the knowledge to predict
         Scientific inquiry
vAn idea can become a
  • Hypothesis (tentative or untested
    explanation)
  • Theory (tested and confirmed hypothesis)
  • Paradigm (a theory that explains a large
    number of interrelated aspects of the
    natural world)
vScientific method
  • Gather facts through observation
  • Formulate hypotheses and theories
          Scientific inquiry

vScientific knowledge is gained through
  • Following systematic steps
    •   Collecting facts
    •   Developing a hypothesis
    •   Conduct experiments
    •   Reexamine the hypothesis and accept, modify,
        or reject
  • Theories that withstand examination
  • Totally unexpected occurrences
    Early evolution of Earth
vOrigin of Earth
  • Most researchers believe that Earth and the
    other planets formed at essentially the same
    time
  • Nebular hypothesis
    • Solar system evolved from an enormous rotating
      cloud called the solar nebula
    • Nebula was composed mostly of hydrogen and
      helium
   Early evolution of Earth

vOrigin of Earth
  • Nebular hypothesis (cont’d)
    • About 5 billion years ago the nebula began to
      contract
    • Assumes a flat, disk shape with the protosun
      (pre-Sun) at the center
    • Inner planets begin to form from metallic and
      rocky clumps
    • Larger outer planets began forming from
      fragments with a high percentage of ices
The Nebular hypothesis




        Figure 1.8
   Early evolution of Earth
vFormation of Earth’s layered structure
  • As Earth formed, the decay of radioactive
    elements and heat from high-velocity
    impacts caused the temperature to
    increase
    • Iron and nickel began to melt and sink toward
      the center
    • Lighter rocky components floated outward,
      toward the surface
  • Gaseous material escaped from Earth’s
    interior to produce the primitive
    atmosphere
       Earth’s “Spheres”

vHydrosphere
  • Ocean – the most prominent feature of the
    hydrosphere
    • Nearly 71% of Earth’s surface
    • About 97% of Earth’s water
  • Also includes fresh water found in streams,
    lakes, and glaciers, as well as that found
    underground
       Earth’s “Spheres”
vAtmosphere
  • Thin, tenuous blanket of air
  • One-half lies below 5.6 kilometers (3.5
    miles)
vBiosphere
  • Includes all life
  • Concentrated near the surface in a zone
    that extends from the ocean floor upward
    for several kilometers into the atmosphere
       Earth’s “Spheres”

vSolid Earth
  • Based on compositional differences, it
    consists of the crust, mantle, and core
  • Divisions of the outer portion are based on
    how materials behave
    • Lithosphere - rigid outer layer
    • Divisions of Earth’s surface – continents and
      ocean basins
Earth’s layered structure




         Figure 1.13
     Earth system science
vEarth is a dynamic body with many
 separate but highly interacting parts or
 spheres
vEarth system science studies Earth as a
 system composed of numerous parts,
 or subsystems
vSystem – any size group of interacting
 parts that form a complex whole
    Earth system science

vSystem
 • Closed systems are self-contained (e.g., an
   automobile cooling system)
 • Open systems – both energy and matter
   flow into and out of the system (e.g., a river
   system)
     Earth system science
vFeedback mechanisms
  • Negative-feedback mechanisms resist
    change and stabilize the system
  • Positive-feedback mechanisms enhance
    the system
vEarth as a system
  • Consists of a nearly endless array of
    subsystems (e.g., hydrologic cycle, rock
    cycle)
Earth system cycles




      Figure 1.21
    Earth system science
Earth as a system
  • Sources of energy
    • Sun – drives external processes such as
      weather, ocean circulation, and erosional
      processes
    • Earth’s interior – drives internal processes
      including volcanoes, earthquakes, and
      mountain building
  • Humans are part of the Earth system

				
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posted:7/26/2013
language:English
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