Paper 2

• Wave

  A transfer of energy
• Transverse waves

  Where the particles of the medium oscillate perpendicular to the direction of energy transfer
• Longitudinal wave

  Where the particles of the medium oscillate in the same direction of energy transfer
• Medium

  A substance that can ‘carry’ the wave
• Frequency

  How many wavelengths there are every second

  Measured in hertz
• Amplitude

  The maximum displacement of a point on a wave from its equilibrium position

  Measured in meters
• Period

  The time taken for one full wavelength

  Measured in seconds
• Wave speed

  The speed at which energy is transferred/the wave moves through the medium

  Measured in meters per second
• What is the speed of sound?

  330m/s
• What is the speed of light?

  3x10^8m/s
• How to measure the frequency of water waves:

  Place a marker in the tank and count the number of waves passing it each second
• How to measure the wavelength of water waves:

  Use a ripple tank to investigate the properties of water waves

  Place a ruler in the tank and measure the wavelength

  OR

  Use a stroboscope to ‘freeze’ the waves on the bench or floor below the ripple tank and use a ruler to measure the wavelength there
• Size and uses of microwave

  Size - grains of sugar

  Uses - heating water based foods, satellites
• Size and uses of infrared

  Size - single cell

  Uses - transferring thermal energy, tv remote
• Size and uses of visible light

  Size - bacteria

  Uses - to see stuff, photography
• Size and uses of ultra violet

  Size - molecules

  Uses - uv sunbeds, killing bacteria
• Dangers of microwaves

  Can cause heating of body tissues
• Dangers of infrared

  Can cause burns
• What are the primary colours?

  Red

  Blue

  Green
• Size and uses of gamma

  Size - nuclei

  Uses - cancer treatment, killing bacteria
• Translucent

  Partially see through
• Dangers of ultra violet

  Can cause cancer or mutations
• Dangers of visible light

  Over exposure can cause damage to eyes
• Dangers of radiowaves

  Large doses may cause cancer
• Transparent

  Fully see through
• Why are gamma rays and x rays the most dangerous types of radiation?

  They have the highest energies and frequencies

  Can cause our cells to mutate which can lead to cancer
• Dangers of ultra violet rays

  Can cause skin to age prematurely and can increase the risk of skin cancer
• Size and uses of x rays

  Size - atoms

  Uses - medical scanning, security searching
• Size and uses of radio

  Size - buildings

  Uses - radio transmissions, tv signals
• Wave length

  The distance between two identical points on a wave

  Measured in meters

  Smallest section of the wave that you could repeat and produce a continuous wave
• Oscillate

  Moves back and forth
• Medical uses of alpha

  Radiotherapy
• Contamination

  When something radioactive gets into a place we don’t want it
• Irradiation

  Being exposed to a radioactive source
• Half life

  The average time it takes for the number of nuclei of the isotope in the sample to halve
• What can detect radiation?

  A Geiger muller tube
• What stops neutron radiation?

  Boron rods
• What stops gamma radiation?

  Sheet of lead
• What stops beta radiation?

  Thin sheet of aluminium
• What stops alpha radiation?

  Sheet of paper