EVM

• Types of rocks


  • Igneous
  • Sedimentary
  • Metamorphic
• Igneous rocks


  • Made when liquid magma cools to form solid rock
  • Molten rock below the surface is called magma, and lava when it reaches the surface
  • Extrusive igneous rock: if the rock cools quickly, small crystals are formed e.g. basalt
  • Intrusive igneous rock: if the rock cools slowly, large crystals are formed e.g. granite
• Sedimentary rocks


  • Formed by the weathering of existing rocks at the Earth's surface
  • Fossils may be present
  • Sediments (small particles of rocks) accumulate into layers and get pressurised due to the newer deposits above them
  • The sediments are transported by water and wind (erosion)
  • Particles like clays, silts, sands, gravels and small boulders are found in sediments
  • Examples: limestone, sandstone and shale
• Metamorphic rocks


  • Formed from existing rock when heat and/or pressure causes changes in the rock crystals without melting it
  • The changes can be physical, chemical or both
  • Examples: marble and slate
• Exploring for minerals


  1. Prospecting

  2. Remote sensing

  3. Radiation detection

  4. Satellite signals

  5. Satellite images

  6. Geochemical analysis

  7. Geophysics
• Surface mining


  1. Open-pit mining

  2. Strip mining
• Sub-surface mining


  1. Deep mining

  2. Shaft mining
• Factors affecting decision to extract rocks and minerals

  • Costs of exploration and extraction
  • Geology
  • Accessibility
  • Environmental impact assessment
  • Supply and demand
• Environmental impacts of rock and mineral extraction

  • Ecological impacts
  • Pollution (noise, water, land, air, visual)
  • Waste management
• Economic impacts of rock and mineral extraction

  • Provides employment and taxes
  • Income can be used for buying goods, services and investing in infrastructure
• Managing the impact of rock and mineral extraction

  1. Safe disposal of mining waste

  2. Land restoration

  3. Bioremediation

  4. Making lakes and natural reserves

  5. Using as landfill sites
• Sustainable resource


  A resource that can be continuously replenished
• Sustainable development


  Development that meets the needs of the present, without compromising the ability of future generations to meet their own needs
• Strategies for the sustainable use of rocks and minerals

  1. Increasing the efficiency of extraction

  2. Increasing the efficiency of use

  3. The need to recycle

  4. Legislation
• Formation of coal


  1. Huge forests grew millions of years ago covering most of the Earth

  2. The vegetation died and formed peat

  3. The peat was compressed between layers of sediments to form lignite (low-grade coal)

  4. Further compression formed coal
• Formation of oil and natural gas


  1. Small animals and plants die and fall to the bottom of the sea

  2. Their remains are covered by sediments

  3. As the sediments start forming layers, they start to change into sandstone as the temperature and pressure increase

  4. The heat and pressure turn the remains into crude oil and natural gas

  5. They separate and rise through the sandstone, filling in the pores

  6. The rock above the oil and gas is impervious (non-porous), so they get trapped underneath it

  
• Types of energy sources

  • Non-renewable (Fossil fuels, Nuclear power)
  • Renewable (Geothermal, Hydro-electric, Tidal, Wave, Wind, Solar, Biofuels)
• Renewable energy sources


  • Limited
  • Take millions of years to get replenished
  • Can be used over and over again
  • Can be replenished in a short period of time
• Non-renewable energy sources


  • Limited
  • Take millions of years to get replenished
• Nuclear fuels last for centuries and are a good replacement for fossil fuels, but the source material (uranium) is limited
• Biofuels may become limited, but it can be renewed by replacing the cut-down trees with new ones to obtain bioethanol and wood. Biogas can be obtained by recycling waste products
• How energy sources are used to generate electricity

  Turbine: a machine, often containing blades, that is rotated by a flow of fluid (such as water, steam, or air)

  
• Reasons for increasing energy demand worldwide

  • Increasing population size
  • Increasing industrialisation and urbanisation
  • Improvements in standards of living and expectations
• Types of energy sources

  • Non-renewable
  • Renewable
• Non-renewable energy sources


  • Limited
  • Take millions of years to get replenished
• Renewable energy sources


  • Can be used over and over again
  • Can be replenished in a short period of time
• Non-renewable energy sources


  • Fossil fuels (coal, oil and natural gas)
  • Nuclear power (using uranium)
• Renewable energy sources


  • Geothermal power
  • Hydro-electric power
  • Tidal power
  • Wave power
  • Wind power
  • Solar power
  • Biofuels e.g. bioethanol, biogas and wood
• Nuclear fuels


  Last for centuries and are a good replacement for fossil fuels, but the source material (uranium) is limited
• Biofuels


  • May become limited, but it can be renewed by replacing the cut-down trees with new ones to obtain bioethanol and wood
  • Biogas can be obtained by recycling waste products
• How energy sources are used to generate electricity

  1. Turbine: a machine, often containing fins, that is made to revolve by gas, steam or air (it is connected to a generator)

  2. Generator: a machine that converts mechanical energy into electrical energy

  3. Fossil fuels and biofuels: These produce a massive amount of energy during combustion that is used to heat water and convert it into steam, which thereby drives the turbines

  4. Nuclear power: Uranium, a radioactive element, releases huge amounts of energy when nuclear fission (splitting of the atom) occurs. This energy is used to heat the water, produce steam, and rotate the turbines

  5. Geothermal power: Cold water is pumped under pressure into a layer of hot rocks. The rocks heat the water. The hot water returns to the surface under pressure and heats the second supply of water using a heat exchanger. The steam produced in the second supply moves the turbine, generating electricity

  6. Wind power: Wind turbines have shafts (blades) that rotate due to wind. Gearbox maximises the rotation of the shaft. Brakes slow down or stop the rotor in very windy conditions, preventing damage to the blade. As the turbine rotates, the generator produces electricity

  7. Solar power: Uses photovoltaic cells that produce a small electric charge when exposed to light. A bank of cells organised into solar panels produce a significant amount of electricity

  8. Tidal power: Uses the natural rise and fall in the level of water in an area. When the levels drop, water is held back by a tidal barrage (a small dam that releases water back through a turbine)

  9. Wave power: Also uses turbine and generator. Uses the smaller differences in water levels that are caused by wind

  10. Hydro-electric power: Uses a dam on a river to store water in a reservoir. Water is released from the reservoir that flows through the turbine, rotating it. The turbine then activates a generator that generates electricity
• Advantages of fossil fuels

  • Plentiful supply
  • Provides job opportunities (mining and processing)
  • The technology used is well-known and the methods of extraction are well-practised

  
• Disadvantages of fossil fuels

  • Carbon dioxide and toxic gases are released when burnt ؞ contributes to global warming
  • Damages local area
  • Limited supply (non-renewable)

  
• Advantages of biofuels


  • Renewable source
  • Growing more plants uses carbon dioxide
  • Plentiful supply
• Disadvantages of biofuels


  • Carbon dioxide and toxic gases are released when burnt
  • Shortage of land for agriculture ؞ increase in food prices
  • Removal of natural ecosystems ؞ reduction in biodiversity
• Advantages of nuclear power

  • Does not produce carbon dioxide
  • Large amount of energy is produced with a small amount of fuel
  • Provides job opportunities
• Disadvantages of nuclear power

  • Risk of radiation leakage
  • Radioactive waste cannot be recycled since it is active for centuries
  • Limited supply (non-renewable)
• Advantages of geothermal power

  • Does not produce carbon dioxide ؞ doesn't contribute to global warming
  • Unlimited supply (renewable)
• Disadvantages of geothermal power

  • Expensive to install
  • Only certain areas have suitable conditions
• Advantages of wind power

  • Does not produce carbon dioxide ؞ doesn't contribute to global warming
  • Renewable