PHYSICS

PHYSICS

P1
1. The Solar System
  1. Asteroids and comets are made of things left over from the formation of the solar system.
  2. Comets are balls of rock dust and ice which orbit the sun
  3. Asteroids are smallish lumps of rubble and rock
2. Beyond the solar system
  1. Universe: 14,000 million years old
  2. Sun: 5000 million years old
  3. Earth: 5000 million years old
  4. Speed of light: 300,000km/s
  5. 1 light year is 9,460,000,000,000km
3. Looking into Space
  1. Radiation can tell us a lot about stars and galaxies
  2. Angle of paralax
  3. Measure brightness to find distance of stars
  4. Sun 150 million km away from Earth
  5. sun 4.2 light years away
  6. Takes light 8 seconds to get to Earth
4. The Life of the Universe
  1. Universe is expanding
  2. Big bang gave galaxies the force to move away
  3. Greater the redshift, faster it is moving away
  4. Red shift is the wavelength of light given off by a galaxy as it moves away
5. The Changing Earth
  1. Rocks provide a record for changes in the Earth
  2. Rocks are constantly recycled
6. Seismic Waves
  1. Earthquakes cause different kinds of seismic waves
  2. P-Waves
    1. Travel through solids and liquids
    2. Faster than S-Waves
    3. Longitudinal
    4. eg. sound and ultrasound
    5. Vibrations in the direction that the wave is travelling
  3. S-Waves
    1. Only travel through solids
    2. Transverse
    3. Vibrations at 90* to direction of trave
  4. Change speed through different materials
  5. Speed=frequency x wavelength
P2
1. Electromagnetic Radiation
  1. 1. Radio waves 2. Micro Waves 3. Infra Red 4. Visible Light 5.Ultraviolet 6. X-Rays 7. Gamma Rays
  2. Energy transferred in packets called photons.
  3. Gamma photons have the most energy and the highest frequency
  4. Emitted from a source
  5. Transmitted, reflected or absorbed
  6. Intensity decreases as distance increases
2. Analogue and Digital Signals
  1. Analogue signals vary
  2. Digital is either on or off
  3. Digital signals are easier to clean up after being amplified
  4. Digital easier to process with computers
  5. Digital can transmit several signals at once
3. The carbon cycle
  1. Being upset
  2. More CO2 released- planes, cars etc
  3. Growing population- space made by chopping down trees
4. EM Radiation and the Atmosphere
  1. Lots of infra red energy is absorbed by gases in the atmosphere
  2. Some radiation from the sun passes through the Earths atmosphere
  3. Ozone protects us from too much UV
  4. Greenhouse effect helps regulate temperature
  5. Earth absorbs EM radiation from the sun and warms the Earths surface up
  6. Light and radio waves pass through most easily
  7. Ozone=O3
5. Uses of EM Radiation
  1. Non-ionising radiation doesn't have enough energy to charge atoms so it transfers energy and heats
  2. Microwaves make particles vibrate,heating them up
  3. Microwaves are strongly absorbed by water molecules so heat very quickly
6. Ionisation
  1. Some EM radiation causes this
  2. High energy EM radiation is more harmful
  3. Dangerous if its in your cells
  4. When a photon loses an electron
  5. Can kill cells
  6. Increased exposure=more damage
  7. Cells divide over and over
P3
1. Electrical Energy
  1. Power is the rate of energy transfer
  2. Energy transferred=power x time
  3. Power=Voltage x Current
  4. Efficiency=energy usefully transferred/total energy supplied
2. Sankey Diagrams
  1. Energyy is always conserved even if it's wasted
  2. Thickness of arrow represents amount
3. Saving Energy
  1. Home
    1. Hot water tank jacket
      1. Double glazing
        Energy saving bulbs
        draught proofing
        loft insulation
        Turn unused appliances off
  2. Public transport/car share/cycling/walking
    1. Recycling
4. Energy Sources and Power Stations
  1. non renewable fuels
    1. Fossil fuels; coal, oil, natural gas
    2. Nuclear fuels (uranium, plutonium)
  2. Renewable fuels
    1. wind
      1. waves
        Tides
        Hydroelectric
        Solar
        Biofuels
        Geothermal
5. Nuclear Energy
  1. Release energy by splitting atoms
  2. Heat evaporates water, steam drives turbine, generator converts kinetic energy into electricity
6. Biofuels, Geothermal and Hydroelectricity
  1. Biofuels are made from plant waste
  2. Geothermal energy is heat from underground
  3. Hydroelectricity uses dams to catch the rain
    1. Requires flooding a valley
7. Generators and the National Grid
  1. Moving a magnet in a wire coil induces a voltage
    1. As you move the magnet through the coil the magnetic field in the coil changes and and induces a voltage and a current if the circuit is complete
  2. Energy is distributed via the national grid
    1. Distributed at a high voltage
      1. High current loses too much heat
8. Comparison of energy resources
  1. Coal
    1. 36% effiicient
    2. 8000 million units produced/year
    3. 920g CO2 per Unit
    4. Site life- 50 years
    5. Cost of energy-2.4-4.5p
  2. Gas
    1. 50% efficient
    2. 5000 million units produced/year
    3. 440g-CO2 per unit
    4. Site life- 30 years
    5. Cost of energy- 2-3p
  3. Nuclear
    1. 38% efficient
    2. 7000 million units produced per year
    3. 110g- CO2 per unit
    4. Site life 25 years
    5. Cost per unit- 4-7p
  4. Wind
    1. 35% efficient
    2. 150 million units produced/year
    3. 0g -CO2 per unit
    4. Site life 25 years
    5. Cost per unit- 3-4p

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	Criado por anna.mat1997 mais de 10 anos atrás