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+ JMJ Chapter 5: Earth’s Energy and Mineral Resources Faustina Academy Earth Science Section 1: Nonrenewable Energy Resources Energy ability to cause change Nonrenewable energy resources energy resources used faster than natural processes can replace them Fossil fuels Coal, oil, natural gas Formed from remains of plants and other organisms buried and altered over millions of years Uses of Fossil Fuels Coal Generates electricity Oil A.K.A. petroleum Lubricant Produces gasoline and other fuels, plastics, shingles, asphalt, wax Natural gas Heats buildings Source of sulfur Coal Rock containing at least 50% plant remains Most abundant fossil fuel (pg. 121) If the consumption of coal continues at current rate, coal supply will last 250 years Begins to form when plants die in swamp Dead plants covered by plants, water, and sediment are not in contact with oxygen, causing slow decay Bacterial growth causes breakdown of molecules in plant tissue, leaving carbon and some impurities behind, forming coal after millions of years Bacteria also cause release of methane gas, carbon dioxide, ammonia, and water Hydrocarbons are extracted from coal to form liquid and gaseous synthetic fuels These liquid fuels can then be processed to produce gasoline for automobiles and fuel oil for home heating Gaseous synthetic fuels can be used to generate electricity and to heat buildings Stages of Coal Formation As decaying plant material loses gas and moisture, carbon becomes concentrated, resulting in peat Peat Layer of organic sediment containing water and impurities When peat is buried under more sediment, it changes into lignite Soft brown coal with much less moisture Releases more energy and less smoke when burned Bituminous coal Compact, black, brittle Provides lots of heat energy when burned Contains sulfur, a pollutant Anthracite coal Forms if enough heat and pressure is applied Contains most carbon of all forms of coal and burns the cleanest Oil and Natural Gas Two other fossil fuels consisting of hydrocarbons, that provide large quantities of energy Oil Thick, black liquid Natural gas Forms under similar conditions and often with oil, but forms in gaseous state • Petroleum Forms over millions of years from remains of tiny marine organisms in the ocean sediment As plankton are deeply buried, temperature and pressure increase, causing a change into oil and gas Oil and natural gas are often found in layers of rock that have become titled or folded (pg. 123) Oil and natural gas are forced upward because they are less dense than water Rock layers that are impermeable, such as shale, stop this upward movement and trap oil and natural gas Reservoir rock Rock layer beneath shale in which petroleum and natural gas accumulate Removing Fossil Fuels From the Ground Coal mining Strip mining Underground mining Coal Mining Strip mining Layers of soil and rock removed and piled Exposed coal removed and transported Used when coal is not deep Mining companies put dirt back, add topsoil, plant grass, trees, and may reintroduce animals Slope mining • Angled opening and air shaft are made in the side of mountain to remove coal Removing Fossil Fuels From the Ground Oil and natural gas are fossil fuels pumped from underground deposits Wells are drilled through rocks where these resources might be trapped Reserve Amount of fossil fuel extracted at a profit using current technology Resource Amount of fossil fuel extracted in useful amounts (but not necessarily for a profit) Methane Hydrates Methane Main component of natural gas Recent studies found new source of methane Methane hydrates Stable molecules found hundreds of meters below sea level in ocean floor sediment Form under conditions of low temperature and high pressure More carbon is contained in methane hydrates than in all current fossil fuel deposits combined Large supplies are thought to be off the eastern coast of the US Highly flammable Difficulties in removal Conserving Fossil Fuels Fossils fuels Take millions of years to form Used much faster than Earth processes can replenish them Turning off lights, computers, TV's, etc., reduces fossil fuel waste Keeping doors and windows shut when AC is on Energy From Atoms Most electricity in US generated in power plants using fossil fuels Nuclear energy Alternate energy source produced from atomic reactions When the nucleus of heavy element is split, lighter atoms form and energy is released This energy can be used for electricity or to power submarines Nuclear fission Splitting of heavy elements to produce energy Carried out in power plants using a type of uranium as fuel Electricity From Nuclear Energy Within a nuclear power plant, there is a large chamber called a nuclear reactor Within the nuclear reactor, uranium fuel rods sit in a pool of cooling water Neutrons are fired into fuel rods When Uranium-235 atoms are hit, they break apart and fire out neutrons that hit other atoms, beginning a chain reaction and releasing a lot of heat energy Heat is used to boil water to make steam, which drives a turbine that turns a generator to produce electricity Nuclear energy is a non-renewable energy source because it uses U-235 as fuel Nuclear Energy Another problem with nuclear energy Waste material produced, radioactive elements that will remain for thousands of years This problem could be solved if useable energy could be obtained from fusion Fusion reaction Source of the Sun's energy that is constantly occurring Materials of low mass are fused together to form substance of higher mass Fusion of hydrogen and helium would be ideal Hydrogen is in abundance in ocean water and the waste is much less dangerous than from fission reactions Scientists need to develop way to achieve high temperatures and high pressure in order to perform a fusion reaction Section 2: Inexhaustible Energy Resources Will not run out in the future Include sun, wind, water, and geothermal energy Solar energy Energy from Sun The sun's energy heats Earth and it causes circulation in Earth's atmosphere (wind) and oceans (currents) Solar Energy Solar energy can be used in an active or passive way Passive South-facing windows collect sunlight and warm the room Active Solar collectors actively collect energy from sun and transform it into electricity Solar energy powers streetlights, calculators, even cars Clean and inexhaustible However, solar cells work less efficiently on cloudy days and cannot work at night Some systems use batteries to store solar energy for use at night or cloudy days, but it's difficult to store energy in batteries Wind Energy Used to power sailing ships Windmills used to pump water or grind corn Wind farm Today wind turbines used to generate electricity Few regions of the world have winds strong and steady enough to produce electricity Energy From Water Hydroelectric energy Electricity produced by water power E.g., Dam is built to contain water As water is released it’s force turns turbines that turn generators to make energy Micro hydroelectric power Waterwheels used to grind grain or cut lumber Geothermal energy Energy obtained by using hot magma or hot, dry rocks inside earth (pg. 133) Water becomes steam when it is pumped through broken, hot, dry rocks The steam is then used to turn turbines that run generators to make electricity Hot dry rocks can be found almost anywhere Renewable Energy Resources Can be replaced in nature or by humans within a relatively short period of time (within a human life span) Biomass energy Energy derived from burning organic material such as wood, alcohol, and garbage Major source of renewable energy Energy from wood Through burning, gives off stored solar energy as heat and light energy However, gases and small particles released when burned Energy from Alcohol Biomass fuel changed to alcohol (ethanol) and mixed with gas (gasohol) Gasohol used like gasoline Reduces amount of fossil fuel needed Problem: growing corn and distilling ethanol uses more energy than amount received in ethanol Energy From Garbage • 2/3 of what is thrown away could be burned If more garbage used for fuel, more fossil fuels could be saved Burning garbage is cheap source of energy and reduces landfills However, burning garbage produces toxic ash residue and pollution Metallic Mineral Resources Mineral resource A deposit of useful minerals Metallic mineral resources Metals obtained from Earth materials Ores Deposits in which a mineral(s) exists in large enough amounts to be profitably mined Ores To be an ore, the mineral must be in demand Enough of it must be present to make it worth removing Must be fairly easy to separate mineral from the material in which it is found Refining Ore After metallic ore is mined from Earth's crust, it is crushed and the waste rock (gangue) removed Refining produces a pure or nearly pure substance from ore E.g., iron can be concentrated from the ore hematite, composed of iron oxide. The concentrated ore can then be purified through smelting (pg. 138) Smelting Chemical process that removes impurities from metal Chemical is added to iron ore and combines with oxygen, leaving behind pure iron During this process, a resource (fossil fuel) is used to get another resource (iron) Nonmetallic Mineral Resources Mineral resources not used as fuels or as sources of metals Can be divided into two groups Industrial minerals Building materials Industrial Materials • • • • E.g., sandstone • Source of silica, used to make glass E.g., sylvite • Used to make potassium fertilizer E.g., halite • Used to make salt E.g., corundum and garnet • Abrasives that can be glued to make sandpaper Building Materials Aggregate One of the most important nonmetallic mineral resources Composed of crushed stone or a mixture of gravel and sand Can be mixed with cement and water to make concrete Limestone Used as a paving stone and as part of concrete mixtures Gypsum Soft, lightweight Used to make plaster and wallboard Rock Used as building stone E.g., granite, limestone, sandstone Recycling Mineral Resources Mineral resources are nonrenewable Require millions of years to form Recycling Using old materials to make new ones Reduces demand for new mineral resources Uses less energy than it takes to obtain new material Saves the material so we don't run out as soon Important because most mineral resources are imported