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P8 (Space (Big Bang (Red-shift (Moving away = larger wavelength = red,…

- - - - Moving away = larger wavelength = red
      - Moving towards = smaller wavelength = blue
      - Faster = more red
    - - Cosmic microwave background radiation
      - Radiation coming from all directions
      - High frequency/energy radiation stretched over time
  - - - Some radiation absorbed/reflected by atmosphere
      - Earth's surface radiates infrared back into space
      - Some infrared radiation back by atmosphere
      - Earth receives EM waves, including IR & UV
  - - - 24h for one orbit
      - 36,000km above Earth's surface
      - Remain in fixed position above equator
      - Communication, satellite TV
    - - 2h orbit
      - Up to 2000km above surface
      - Orbits over poles
      - Military, observation, weather
    - - 24 satellites around the Earth
      - Uses three satellites to triangulate your position
  - - - 1) Huge cloud of dust & hydrogen
      - 2) Gravity pulls matter together
      - 3) Central core gets hot enough for fusion
      - 4) Balance between gravity inwards & expansion of gas outwards
      - NB) Sun is main sequence star
    - - 1) Hydrogen used up, fusion slows down
      - 2) Core cools, gravity pulls layers inward
      - 3) Core heats up, expands to red giant or supernova
      - 4) Leave behind white dwarf or neutron star/black hole
  - - - Solid inner core
      - Liquid outer core
      - Solid mantle core, but can flow (hot)
      - Solid crust
      - 6370km radius
    - - P-waves
        
        Primary waves (faster)
        
        Longitudinal waves (like sound)
        
        Can travel through solids & liquids
        
        Shadow zone - refraction when changing medium (e.g. mantle & outer core)
      - S-waves
        
        Secondary waves (slower)
        
        Transverse waves
        
        Cannot travel through liquids
        
        Shadow zone - do not travel through liquid outer core
- - - - State of brakes
      - Road surface
      - Weather conditions
    - - Thinking distance: 15m
      - Braking distance: 38m
  - - - Drinking alcohol
      - Tiredness
      - Distractions
      - Drugs
- - - - Live wire: brown
      - Neutral wire: blue
      - Earth wire: green/yellow
    - - Earth wire connects case to pole in ground, prevents electrocution
      - Fuse melts & switches off circuit
      - Case made of plastic so no current flows, 'double insulated', no earth
  - - - Biofuels
      - The Sun
      - Tides
      - Wind
      - Geothermal
      - Expensive, CO₂ in manufacture, specific
    - - Nuclear fuels
      - Fossil fuels (e.g. coal, oil, gas)
    - - Heating (fuels, solar, geothermal)
      - Transportation (fuels)
      - Electricity (solar, wind, tidal, etc.)
  - - - Population (from 1bn to 7bn)
      - Use of devices
      - Electricity generation
    - - Supply of fossil fuels is finite
      - CO₂ contributes to the greenhouse effect
      - Renewable energy is expensive