Rocks and weathering

• Crust


  10-100km thick
• Mantle


  Solid but can flow slowly
• Outer core


  Liquid of molten nickel and iron
• Inner core


  Solid made out of iron
• Why is the outer core liquid

  The temperature of the iron and nickel is above their melting point
• Why is the inner core solid

  The pressure here is SO high.The particles remain in a regular arrangement like a solid
• Earth's atmosphere


  • Divided into main layers
  • Thins out in each higher layer until the gases disperse in space
• Igneous rocks


  Are hard and contain interlocking crystals of different sizes
• How are igneous rocks formed

  Molten rocks cool down and form a solid rock
• How are fossils made?

  • When plants or animals die bacteria in the air and soil.Break down the soft parts by decay
  • If they are buried between the layers of sedimentary rock, there will be no oxygen and no bacteria.So the dead plant or animal remains become preserved
  • Finally over millions of years Minerals from the surrounding rock replaced the animal and plant so remain and turns it into a fossil
• Why are fossile never found in igneous rocks

  If the dead remains of plants or animals are found near volcano they may melt because of the very high temperature
• Metamorphic rocks


  Formed inside a sedimentary rocks and are changed because of high heat and pressure
• Types of meramorphic rocks

  Mudstone > Slate (roofs)

  Limestone > Marble (statues and construction)

  Sandstone > Quartzite
• Weathering


  When rocks break down into smaller pieces
• Freeze-thaw (needs water to happen)

  1. Water gets into cracks of rocks

  2. Water freezes and expands

  3. Cracks get bigger and the rock breaks
• Exfoliation


  1. Rock expands because of heat during the day

  2. Rock contracts when it cools at night

  3. Layers of rock begin to peel off like an onion
• Chemical weathering (rain)


  1. Reacts with rock in buildings and statues

  2. Causes them to crumble and break apart

  3. Most affected are marble, chalk and limestone
• Biological weathering


  1. As plants and shoots grow, they push their way through the rock

  2. This forces the rock to break apart
• Weathering needs water to happen
• What pH is acid rain

  Lower than 5.6
• Acid rain

  Sulphur (s) + oxygen (O2) > Sulphur dioxide (SO2)
• Effects of acid rain


  • Corrodes and weathers buildings
  • Making rivers acidic- killing aqua life
  • Corrodes trees, killing them
• Quarry


  Where limestone and other materials are mined from the ground using explosives
• Building materials


  • Limestone
  • Sandstone, slate
• Limestone


  • Composed of calcium carbonate
  • Easy to cut but hard enough to be used as building blocks
• Sandstone


  • Hard enough to be used as building blocks
  • Can be split into thin layers
• Slate


  • Water-proof
  • Useful for roofing
• What happens to

  1. Limestone rocks are cut into useful chunks

  2. Sent to where they are needed to make other building materials
• Ore


  A rock that contains minerals which are valuable and worth extracting for money
• Quarry


  An area where limestone or other raw materials are mined from the ground using explosives
• Rock cycle


  When rocks change from one type to another over a long period of time
• Igneous > sedimentary > metamorphic
• Most metals are too reactive to exist on their own outside the ground.So they are combined with other elements, mostly oxygen or sulphur As a compound they have to be extracted from ores
• A few metals are so unreactive that they exist on combined as pure metals, for example, gold.And silver
• Ceramic


  Materials that are hard heat resistant and made out of pottery bricks and glass
• Common uses of ceramics

  • Plates
  • Sinks
  • Pottery
  • Cups
  • Tiles
  • Replacement teeth
• Composite


  Materials are made of 2 or more different types of materials that combine the properties of the two materials to make a more useful one
• Polymers


  Long chains of repeating small molecules (monomers) joined together for example plastics or rubber
• • Potassium
  • Sodium
  • Calcium
  • Magnesium
  • Aluminium (extracted by elctrolysis)
• • Zinc
  • iron
  • lead
  • copper (extracted with reduction, carbon)