Earth Science Spring 2013

 Nonrenewable resources- substance of limited supply that cannot be replaced  Renewable resources- substance that can be replaced  Ores- deposit of minerals from which metals and nonmetals can be profitably removed  Veins- narrow band of mineral deposits in rock  Lode- deposit formed by thick mineral veins

 Placer deposits- fragments of native metals that are concentrated in layers at the bottom of a stream bed  Gemstones- nonmetallic mineral that is brilliant and colorful when cut

 Minerals are nonrenewable resources because the processes that form them take millions of years  Air, water, and plants are renewable resources and can be replaced within a human lifetime or as they are used

 Formation of Ores Most metallic and nonmetallic elements are found in chemically combined forms as minerals in the crust. Minerals are found in ore deposits.  Ex: iron is found in magnetite & hematite  Ex: mercury is found in cinnabar  Ex: aluminum is found in bauxite

Ores & Cooling Magma  As magma cools, dense metallic minerals accumulate and form ore deposits within the hardened magma  Ex: Cr, Ni, Pb Ores & Contact Metamorphism  Some ores form through contact metamorphism when hot magma comes into contact with existing rock  Heat & chemical fluids from the magma change the surrounding rock  Hot minerals spread through small cracks in a large mass of rock & may deposit valuable minerals in veins  A large # of thick mineral veins form a deposit called a lode

Ores & Moving Water  Movement of water forms ore deposits in 2 ways:  1: Fragments of native metals are released as rocks break down due to natural processes  Streams carry the fragments until they are deposited where currents are weak and they become deposited in placer deposits  2: Water dissolves minerals as it flows through cracks in rocks on the earth’s surface  New minerals precipitate out of the solution forming ore deposits called veins  Ores of heavy metals often form this way

 Uses of Mineral Resources Some metallic ores are prized for their beauty and rarity  Ex: gold, platinum, & silver Other metallic ores are sources of valuable elements Some nonmetallic minerals are gemstones, which are rare crystals cut & used in jewelry because of their brilliance & color Other nonmetallic minerals are used as building materials  Ex: calcite & gypsum

 Mineral Conservation use other more abundant or renewable materials in place of minerals  Ex: plastics Recycling  Ex: metals like iron, copper, & aluminum  Ex: glass & building materials

 Fossil fuels-fuel formed from the remains of living organisms, such as coal, petroleum, & natural gas  Hydrocarbons- compound made up of atoms of carbon & hydrogen  Carbonization- process in which plant materials are changed into carbon  Peat- brownish-black material produced by partial decomposition of plant remains  Lignite- brown coal  Bituminous coal- soft coal  Anthracite- hardest form of coal  Crude oil- unrefined petroleum  Petrochemical- chemical derived from petroleum

 Fossil fuels are formed from the remains of living things. Contain primarily hydrocarbons

 Coal Dark-colored, organic rock Formation of coal  Remains of plants that have undergone carbonization  Carbonization occurs when partially decomposed plants are buried in swamp mud  Bacteria consume some of the plant material & then release marsh gas (CH 4 & CO 2 ).  As the gas escapes the chemical compounds present in the plants gradually change, and only carbon remains.

Types of Coal  Peat  formed from the partial decomposition of plants  a brownish black material  Lignite  Formed when peat deposits are covered by layers of sediment that squeeze water & gases from the peat  Brown coal  Bituminous Coal  Formed from the pressure of more sediments on top of lignite  Soft coal  Most abundant type of coal  Anthracite  Forms where the folding of the earth’s crust produces extremely high temperatures & pressure of bituminous coal  The hardest form of coal  Bituminous coal & anthracite consists of % carbon & produce great heat when they burn

 Petroleum & Natural Gas Mixtures of hydrocarbons Formation of Petroleum & Natural Gas  Remains of microorganisms accumulated on the floors of bodies of water & were buried by sediment.  The sediments limit the available oxygen supply & prevent the remains from decomposing completely  The heat & pressure become great enough that the remains are converted into petroleum & natural gas

Petroleum & Natural Gas Deposits  Petroleum & natural gas form reservoirs when pressure pushes them up through permeable rock.  Petroleum & natural gas get trapped below layers of impermeable rock, often called a cap rock  Uses of Fossil Fuels Main sources of energy for transportation, farming, & industry Crude oil- unrefined petroleum Petrochemicals- components of over 3000 products  Ex: plastics, synthetic fibers, medicines, tars, waves, synthetic rubber, insecticides, ect…

 Fossil Fuel Supplies Coal is the most abundant fossil fuel in the world  Every continent has coal  It is estimated that coal deposits will last about 200 years Petroleum  75% of the petroleum in the U.S. has already been discovered  As much 90% of discovered petroleum in some areas is still in the ground  Oil shale

 Fossil Fuels & the Environment The use of any fossil fuel has a impact on the environment Cause ground, water, & air pollution  Oil spills  Gas leaks  Etc…

 Vocab Nuclear fission- splitting of the nucleus of a large atom into smaller nuclei Nuclear fusion- combination of the nuclei of small atoms to form a larger nucleus

 Nuclear Fission Scientists & engineers have developed technology that uses nuclear reactions to produce energy for commercial use based on nuclear fission  Nuclear fission is the splitting of the nucleus of a large atom into 2 or more smaller nuclei U-235 is the only naturally occurring element used for nuclear fission  Processed into pellets and then put into fuel rods

 U-235 Energy is created when a neutron bombards uranium 235 and the nuclei splits releasing heat the heat can be used to turn a turbine that creates electricity Nuclear reactor is used to do this

 Production of nuclear energy has drawbacks Waste products of nuclear fission give off dangerous radiation, which can destroy plant and animal cells & cause harmful changes in the genetic material of living things Waste used to be dumped into the ocean, but now it is stored in on site water pools or in dry casks Low level wastes can be stored onsite or transported to one of 3 disposal facilities in the US

 Nuclear Fusion All of the energy that reaches the earth from the sun is produced by another kind of nuclear reaction called nuclear fusion In nuclear fusion nuclei of smaller atoms combine & form larger atoms  Ex: Sun – hydrogen nuclei are fused to form helium nuclei  Can only take place at temperatures above 15 million degrees Celsius

 Solar collector- device for capturing solar energy  Geothermal energy- energy contained in and available from water heated by magma or gases within the earth  Hydroelectric energy- energy produced by running water

 Solar Energy Converting sunshine into useful heat can be done in 2 ways  Passive system- requires no working parts  Windows  Active system- involves the use of solar collectors  Solar panels  How solar panels work…  Glass boxes with tubes of water inside & the sun heats the water and the water circulates through the building  Photovoltaic cells  Convert sunshine directly into electricity

 Geothermal Energy Water that is heated beneath the earth’s surface by hot rocks or magma may be used as a heat source  Water can be in contact with the hot rocks or magma or may flow through hot rocks  Steam may also be used as a heat source We use this by drilling wells to reach the hot water or steam and then it is pumped up to the surface to be used

 Geothermal Energy Cont… In Iceland 80% of the homes are heated by geothermal energy Italy and Japan have power plants using geothermal energy

 Energy from running water Hydroelectric energy is energy produced by water running through a turbine that spins and produces power 11 % of the electricity in the US comes from this Dams hold back water and the water is channeled through a plant where it spins the turbines

 Energy from tides Dams are built to trap the water during high tide & release it at low tide The water spins the turbine of an electrical generator  Energy from the wind Wind farms can produce enough energy to meet the electricity needs of entire communities There are only a few places where this is practical Wind doesn’t blow everyday so it cannot be relied on as a total alternative energy source