P4 unit: Radiation for life

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  • Created by: Jen3005
  • Created on: 20-05-16 19:12
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  • P4 unit: Radiation for life
    • Electrostatic charges
      • When you rub two insulating materials together, a charge builds up.
        • Electrons, which have a negative charge are transferred from one material to the next
          • Opposite charges attract. Like charges repel.
      • Opposite charges attract. Like charges repel.
      • Dangers
        • Sparks jumping
        • Shocks
      • Anti-static lines prevent the build up of charge by reducing friction
      • Defibrilators use two charged paddles
      • Electrostatic precipitators
        • Remove smoke particles from waste gases coming from chimneys
        • 1) Charged wire grid.
          • Soot or dust travels through it and also becomes charged.
            • 2) Two metal plates
              • Charged oppositely to that of the grid
              • 3)Dust sticks to the plates
                • 4) Plates hit to remove the dust
          • High voltage
    • Voltage
      • Measure of energy difference
      • Measured in volts
      • Measured using a voltmeter
    • Current
      • Measured in amps
      • AC and DC
      • Charge creates a current
      • How powerfully electrons flow through an item
      • To increase the current you can reduce resistance or increase the voltage
    • Resistance
      • Measured in ohms
      • Current flows through the path of the least resistance
      • How much an item can slow the flow of electrons
    • Electrical safety
      • Blue wire = neutral wire
        • Completes the circuit
        • Has a voltage of 0V
      • Brown wire = live wire
        • Provides energy to the device
      • Green and yellow = earth wire
        • Provides a route to eath
    • Ultrasound
      • Sonar = reflection of sound
      • Body scans
        • Travel through the body to produce images
        • Non-invasive
        • Check baby development
        • Reflect from layers of the body and return at different times, depending on the depth of each layer
      • Kidney stones
        • Vibrate kidney stones inside the body
          • Stones break into small pieces
            • Small enough to pass out of the body
    • Radiation types
      • Alpha
        • Positively charged
        • Move at slow speeds
        • Low penetrating power
        • Very ionising
        • Large
        • Large mass
        • Alpha particles have 2 neutrons and 2 protons
      • Gamma
        • Weak ionising power
        • No mass
        • Highly penetrating
        • No charge
        • Very fast speeds
      • Beta
        • Moderately penetrating
        • Move at fast speeds
        • Negatively charged
        • Moderately ionising
        • Small
        • Small mass
    • Half life
      • Time taken for half of a radioactive sample to decay or for its radioactivity to halve
    • Radioisotopes
      • Tracers
        • Radioactive substances that accumulate in a certain area
        • Use gamma radiation
          • They are very penetrating
        • Can detect leaks
          • Radiation accumulates where the leak is
      • Medical
        • Diagnostic
          • Can scan for tumours
        • Radiotherapy
          • Treats cancer
          • Works to minimise damage to healthy cells
          • Gamma rays scan a set target and rotate around it.
            • This keeps the radiation focused on cells that need to be killed, not the healthy ones.
        • Sterilising equipment
    • Carbon dating
      • When an organism dies, gaseous exchange stops
      • activity of the sample : the activity in living matter calculates the age.
      • The amount of carbon-14 in the atmosphere has remained the same for thousands of years
    • Uranium dating
      • Uranium decays to lead
      • Comparing the ratio of uranium to lead atoms in a sample, its age can be estimated
    • Nuclear fission
      • In order to generate heat, an atom of uranium splits
      • A neutron is fired at an atom so it changes shape and splits
        • In order to generate heat, an atom of uranium splits
        • Neutrons released from split atoms hit other atom, causing a chain reaction
      • Rods are put into the reactor to stop the reaction spreading too far
        • Rods can be pulled up or down to control how many atoms split.
    • Nuclear fusion
      • In stars, the nuclei moves very fast to get close enough to other nuclei to fuse.
        • This is achieved because of the intense pressure and heat. They are moving so fast they smash together
      • Joining two nuclei together
      • The conditions necessary to create nuclear fusion is too intense to be safely reproduced and maintained on earth
      • Fleischman and Pons claimed to have achieved cold fusion and could fuse atoms together at room temperature
        • Nobody has since been able to repeat it so these claims are seen as false
    • Beta decay
      • The numbers on the top of the symbols must be the same.
      • On the bottom of the symbols,he first two numbers must equal the last one
    • Alpha decay
      • There must be two protons and two neutrons
      • When the nucleus emits an alpha particle, it loses 2 protons and 2 neutrons
  • Beta
    • Moderately penetrating
    • Move at fast speeds
    • Negatively charged
    • Moderately ionising
    • Small
    • Small mass

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