Understand the Physical World Around You...
This course takes an in depth and detailed look at each of the major forces that act upon the Earth and it's environments over time.
Students gain an understanding of the different processes involved in the creation of the Earth as we now see it and of the complex interactions that produce modern climates and affect the current environment.
Lesson Structure
There are 9 lessons in this course:
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Structure and Forces
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Scope and Nature of the Earth and it's Structure
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Continental and Oceanic Crust
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Continental Drift
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Sea Floor Spreading
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Plate Tectonics
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Plate Boundaries; divergent boundaries, convergent boundaries
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Transform Faults
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Volcanoes; shield volcanoes, cinder cones, composite conesmagma, pyroclastic flow
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Rocks and Minerals
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Definitions
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Mineral Properties; crystaline form, luster, colour, streak, hardness, light transmissioncleavage, fracture, etc
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Mineral Groups
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Silicates
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Nonsilicate Minerals
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Rocks; formation, texture
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Sedimentary Rocks; derital, chemical and biochemical rocks
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Metamorphic Rocks
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Surface Changes
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Introduction
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Weathering
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Mass Wasting
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Erosion
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Glaciers
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Streams; birth of a stream, stream flow, deposited stream sediment
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Ground Water and Land Subsidence
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Aquifiers and Confining Beds
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Soil; parent materia, time, climate, life forms, slope
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Soil Profile, horizons
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The Oceans
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Scope and Nature of Oceans
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Sea Water
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Currents
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Coriolis Effect
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Geostrophic Flow
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Land Scale Currents
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Convergence and Divergence
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El Nino
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Waves
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Tides
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The Ocean Floor
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Shorelines
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The Marine Food Chain
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Air and Weather
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The Hydrological Cycle
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The Atmosphere
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Atmosphere and Circulation of Essential Elements
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Structure of the Atmosphere, Troposphere, Stratosphere, Mesosphere, Seasons
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Solar Radiation
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The Greenhouse Effect
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Weather
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Temperature Control
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Air Pressure
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Wind; Local Winds, Wind Erosion, Wind in Arid Climates
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Thunderstorms
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Tropical Cyclones
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Tornadoes
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The Greenhouse Effect
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Introduction
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Global Warming
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Anthropomorphic Changes to Global Climates
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Ozone Layer and Ozone Destruction
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Atmospheric Pollutants
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Global Weather Patterns
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Climate
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Climate Classification; Tropics, Dry Climates, Humid Mid Latitude and Mild Climates, Polar Climates, etc
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Geological Time
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Geological Time Scale
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Relative Dating
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Inclusion
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Correlation
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Types of Fossils
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Radiometric Dating; radiocarbon dating, radioactivity, half life
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Geological Time
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Modern Environmental Issues
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Balance of Nature
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Major Current Environmental Events
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Resource Depletion
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Conservation Issues
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Pollution and Waste
Aims
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Describe the major structural elements of Earth and the major internal forces which affect them.
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Classify rocks and minerals according to their characteristics and formation.
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Explain external processes that that cause topographic and soil changes on the earth’s surface.
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Describe the oceans of the earth and their role in global processes.
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Describe the earth’s atmosphere and the forces which create weather.
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Describe some well known effects of particular atmospheric conditions like the Greenhouse effect.
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Identify global weather patterns and their relationship to different climates.
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Describe the way in which the earth’s surface has changed over time.
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Identify environmental issues which are of current significance.
What You Will Do
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Research how a mountain/mountain range in or near your region was formed.
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Explain plate tectonics.
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Collect and classify rock samples as either sedimentary rock, igneous rock, or metamorphic rock.
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Describe four ways that weathering breaks down rocks to help form soil.
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Explain how the speed of a stream affects the shape of the landscape.
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Name the three main layers of the ocean, describe the characteristics and ocean life in each.
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Keep a record of atmospheric and weather changes in your environment.
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Explain the highs and lows associated with air pressure, and how they affect weather.
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Create a questionnaire to determine understanding of the Greenhouse Effect or the Ozone layer.
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Explain why your region has its overall climate.
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Research what life forms (plant and animal) inhabited your region before the formation of humans.
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Identify the rules and laws used to date fossils.
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Research an environmental problem in your area, and discuss possible solutions
What is the Earth's Environment?
The total environment of our earth consists of four major realms or spheres:
- the atmosphere,
- the hydrosphere,
- the lithosphere,
- and the biosphere – the living part of the planet.
Fortunately for life on Earth, many of its natural processes combine to sustain life. The hydrosphere gives us and plants precious water, the thin blue veil of atmosphere supplies the air that we breathe each day, regulates temperature and filters out dangerous solar radiation, and the lithosphere provides the soil in which plants can grow and most of the nutrients for all living things.
In recent years, scientific research has shown that the chemical composition of our atmosphere is changing because of both natural causes and human activity. There is evidence that levels of heat absorbing gases in our atmosphere are increasing, and that other essential parts of our atmosphere are being broken down by human-released chemicals. The problem is one of balance. In balance, processes sustain life; out of balance, these same processes can endanger life. In this course, we examine some of the natural processes that now appear to be changing partly due human activity.
Global Warming
Without the greenhouse effect, the earth would be very cold, with an average temperature of around minus 18 degrees centigrade. The greenhouse effect is an atmospheric condition created by the heat energy radiated by the sun and greenhouse gases that are normally present in the atmosphere. As mentioned in chapter 5, carbon dioxide (CO2) is transparent to shortwave radiation (incoming solar radiation) but not to long wave radiation (outgoing terrestrial radiation). Thus, as solar radiation passes through the atmosphere and warms the Earth, that which is reflected back is absorbed by CO2 & other greenhouse gasses (water vapour, carbon dioxide, methane and nitrous oxide), and the rest is reflected back towards the sun. The energy trapped or absorbed by the greenhouse gasses warms the earth.
The Natural Balance
Venus’s atmosphere is high in CO2 (96%), a greenhouse gas, so that its average surface temperature is 450 degrees centigrade. If the earth’s atmosphere trapped all the sun’s heat that passes through it, the earth’s temperature would continue to rise to those levels. However, the earth’s atmosphere contains only around 0.03% carbon dioxide, which allows much of the sun’s heat to be reflected back into space.
On our planet, the temperature only rises until the amount of infrared or long wave radiation leaving the Earth equals the amount of energy coming in from the sun. This means that the earth receives the same amount of the sun’s energy as it reflects. As long as the amount of greenhouse gases in the atmosphere stays the same, and the amount of heat arriving from the sun stays the same, there is a balance. In this state of balance created by the natural greenhouse effect, the earth has an average temperature of 16 degrees centigrade.
Anthropomorphic Changes to Global Climates
The earth's atmosphere is composed of 78 % nitrogen, 21% oxygen, and only about 1% of greenhouse gases (water vapour, carbon dioxide, methane and nitrous oxide).
Atmospheric concentrations of CO2 have risen from under 1 billion metric ton/year in the early 1800’s to over 8 billion metric tons/year in 2000. It has been concluded by the IPCC (Intergovernmental Panel of Climate Change) that up until the 1950’s some of the variation in the Earths surface temperature can be attributed to natural sources such as solar variation and volcanic eruptions. Post 1950’s however, is attributed solely to human activity. Note that human activity was still impacting only climate, prior to the 1950’s, however it was not the only source. In fact it is thought that humans have impacted upon the climate since the invention of fire and agriculture. There are two main sources of anthropogenic (man made) greenhouse gasses. These are: burning of fossil fuels such as coal, natural gasses and petroleum; and second is deforestation as CO2 is released through decaying vegetation as well as burning vegetation. It has been estimated that approximately 40-50% of CO2 released from deforestation will remain in the atmosphere despite some it being absorbed by other plant growth and the oceans.
Many scientists believe that increases in greenhouse gasses are causing the earth’s temperature to rise, resulting in an enhanced greenhouse effect. Other scientists believe that these changes are just part of the natural cycles of change that continuously occur on earth. While most agree that earth’s temperature is rising, they disagree about how much it will rise, how fast it will rise, and what the effects will be on earth and on living things.
Why Study Earth Science?
Our life on earth is shaped by the environment in which we live. Earth Science helps us to understand how the natural world has formed and the forces that are constantly at work, shaping the landscape. This in term guides us in our efforts to manage our environment and use its limited resources effectively and responsibly. An understanding of Earth Sciences enriches our understanding and helps us to see the world in a new way. It builds the foundation for a challenging career, as humanity struggles to find the balance between human demands and the demands of the natural world.
