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Sci 7- Unit 3- Topics 7-8
Transcript of Sci 7- Unit 3- Topics 7-8
TEMPERATURE 2:47 minutes 2:23 4:14 Topic 7 -
Sources of Thermal Energy Topic 8 -Conserving Our Fossil Fuels Chemical Energy
Chemical Energy can be transformed into Thermal Energy when wood, or coal is burned. Environmental Impacts: pollution caused by the burning of these fossil fuels Electrical Energy
Electricity is produced in many ways. Hydro-electric dams use the force of gravity which pulls the water over the dam to turn turbines, which are attached to generators, which produce the electrical energy from the mechanical energy of the generators. Environmental Impacts: wildlife in the area of the dam lose valuable habitat, there is also pollution by the burning of fossil fuels, heated waste water can affect organisms in lakes where this waste water is dumped. Mechanical Forces
Mechanical forces that push or pull objects often release thermal energy, as do Frictional forces. Geothermal Energy is energy from the interior of the earth.
Ex.'s Volcanoes, hot springs, geysers (See Pg. 240/241) Environmental Impacts: Geothermal energy is clean and renewable. could reduce the threat of oil spills, the pollution caused by burning fossil fuels and the wastes from mining fossil fuels. Solar Energy
Solar energy is clean and is guaranteed not to run out(renewable). It is not available all the time. No Environmental Impacts...wahoo Environmental Impacts: aesthetics
can kill birds and bats intermittent shadows noise More Sources of Thermal Energy
The living organisms burn food (chemical energy) in their bodies to generate body heat (thermal energy).
A composter is another source of thermal energy. Wind Energy
Wind energy is the energy of moving air, and is a result of solar energy and convection. The windmill is a turbine (a wheel with fan blades), which is connected to a generator. When the windmill spins, the generator produces electricity. Free and renewable energy source. Fossil Fuels
Most energy supplies come from fossil fuels. Fossil Fuels are chemicals from plants and other organisms that died and decomposed millions of years ago and have been preserved underground. Ex. (Natural gas, coal, & oil) TELL ME 2 PROBLEMS WITH FOSSIL FUELS The thermal energy from these events can produce hot water or steam. This can then be piped to a power plant at the surface. This can be used to run turbines which produce electrical energy. This is the Volcanoe used in the LORD of the RINGS in New Zealand Two Types:
Passive solar heating - uses the materials in the structure to absorb, store and release the solar energy.
Active solar heating - uses mechanical devices(fans, solar collectors, pumps) to collect and distribute the thermal energy. Decomposers break down food and as these chemical changes occur, thermal energy is produced, which in turn helps speed up the process of decomposition. We have used up about half of our known, easy-to-obtain fossil fuels. See Fig. 3.37 on Pg. 245
Since fossil fuels take millions of years to form, they are called non-renewable resources.
Energy sources that can be replaced in 100 years or less are called renewable resources. Ex. Trees, crops. Burning fossil fuels produces carbon dioxide gas.
CO2 is a greenhouse gas. Heat is unable to escape
the Earth's atmosphere and Global Warming occurs. Canadians are one of the highest producers
of greenhouse gases per person in the world. Cogeneration uses waste energy to generate
electricity or heat buildings. Thermal pollution is the accidental
warming of the environment.