Social science

• The earth's surface is a vast area of 500 million square kilometers where four vast open systems interact
• System


  A functional whole, composed of organized, Interacting, Interdependent parts
• Physical systems


  Also known as the natural systems
• Spheres


  • Atmosphere
  • Hydrosphere
  • Lithosphere
  • Biosphere
• Environmental Spheres


  • Abiotic (non-living)
  • Biotic (living)
• Abiotic Spheres


  • Atmosphere
  • Hydrosphere
  • Lithosphere
• Biotic Sphere


  Biosphere (ecosphere)
• Earth's four major spheres or systems

  • Hydrosphere
  • Biosphere
  • Lithosphere
  • Atmosphere
• Atmosphere


  • The gaseous blanket of air that envelops, shields, and insulates the earth
  • The movements and processes of the atmosphere create the changing conditions that we know as weather and climate
• Biosphere


  • Composed of all living things: people, other animals and plants
• Lithosphere


  • Comprised of the solid earth-rocks, soil, landforms and the minerals
• Hydrosphere


  • Comprised of the waters of the earth-oceans, lakes, rivers & the glaciers
• It is the nature of these four major subsystems and the interactions among them that create and nurture the conditions necessary for life on Earth
• The impact and intensity of interactions among earth's subsystems are not identical everywhere on our planet, and it is these variations that lead to the geographic patterns of environmental diversity
• Physical Systems

  • Atmosphere
  • Lithosphere
  • Hydrosphere
  • Biosphere
• Processes in the physical system


  • Atmospheric processes
  • Geomorphic processes
  • Tectonic Plate Movements
  • Biotic processes
  • Hydrologic processes
• The atmosphere of the earth extends nearly 563 km (350 miles out) from the solid surface of the Earth
• The atmosphere is made up of a mixture of different gases that combine to allow life to exist on the planet
• Gases in the lower layer atmosphere

  • Nitrogen (78%)
  • Oxygen (21%)
  • Carbon dioxide (vital to plant growth)
• Layers of the atmosphere

  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere
• Troposphere

  • The lowest of the atmospheric layers and extends from the earth's surface up to about 14 km in altitude
  • It extends to about 17km above the sea level at the equator and about 8km over the poles
  • The thickness of the troposphere varies with altitude and the seasons
  • The outer boundary of the troposphere is the tropopause
  • All human activities occur in the troposphere
  • It is the layer where all weather we experience takes place
• Stratosphere


  • Beyond the tropopause
  • Temperature remains constant to a height of about 20 km and then begins a gradual increase that continues until the stratosphere
  • Temperatures increase in the stratosphere because it is in this layer that the atmosphere's ozone is concentrated
  • The ozone absorbs ultraviolet radiation from the sun as a result, the stratosphere is heated
  • Most commercial aircraft travel takes place in the lower part of the stratosphere
• Ozone Layer


  • Contained within the stratosphere, mainly located in the lower portion from about 15-35 km
  • Absorbs most of the sun's ultraviolet radiation, especially UVB
• Mesosphere


  • Above the stratosphere, a middle layer separating the lower stratosphere from the Thermosphere, extending from 80 to 90 km
  • Military aircraft travel at much higher altitude with some classified stealth aircraft
• Thermosphere


  • The change over from the Mesosphere begins at the height of 80km
  • The temperature in this layer is very high due to gases moving at very high speeds
  • The Aurora Borealis (northern lights) and Aurora Australis (southern lights) occur in this layer
• Ionosphere


  • Part of the atmosphere that is ionized by solar radiation
  • Overlaps both the exosphere and the thermosphere
  • Forms the inner edge of the magnetosphere
  • Influences radio propagation on Earth
  • Responsible for auroras
• Hydrosphere


  The combined mass of water found on, under, and over the surface of the earth
• Water is the most distinctive substance found on earth, it set the stage for the evolution of life and is still an essential ingredient of all life today
• Surface water occupies 97% of the surface area of the earth
• Forms of water on Earth

  • Liquid (seas, rivers)
  • Solid (ice)
  • Gas (water vapour)
• The great majority of the world's moisture is in the form of liquid
• Water Cycle


  The circulation system which carries water from the oceans, through the atmosphere, to the land and back to the sea
• The water cycle is a closed system, no water actually leaves the circulation system
• The water cycle is powered by the energy from the sun
• Water is a renewable resource, if used and managed properly it can be replaced or renewed
• Processes in the water cycle

  • Evaporation
  • Condensation
  • Precipitation
  • Infiltration
  • Runoff
  • Transpiration
• Evaporation


  The process by which water changes from a liquid into a gas and becomes water vapor
• Condensation


  The reverse of evaporation, when water vapor changes from a gas to a liquid
• Transpiration


  The process by which plants discharge water vapour into the atmosphere
• Evapotranspiration


  The combined water loss into the atmosphere from evaporation and transpiration