ENERGY

The Use of Waves and Universe Expansion – Remember it!

The Use of Waves and Universe Expansion – Remember it!

  • Waves are made of vibrations which transfer energy from one place to another.
  • Some waves need to travel through a medium while others don’t.
  • With transverse waves the oscillations (another terms for vibrations) are at right angles to the direction of travel and energy transfer.
  • With longitudinal waves the oscillations move in the same direction as the direction of travel and energy transfer.
  • The pattern formed by longitudinal waves includes areas of rarefaction and compression.
  • The maximum disturbance of a wave is known as its amplitude.
  • The wavelength is the distance between two waves.
  • The frequency of a wave is how many waves are produced each second from a source or that pass a particular point each second.
  • v = f x ?
  • Refraction is when sound or light waves travel from one medium to another and changes direction.
  • Diffraction is when a wave meets a gap within a barrier then it travels through but spreads out a little into a region beyond the gap.
  • When a wave, like sound or light, reflects from a surface it obeys the law of reflection which states: the angle of incidence equals the angle of reflection.
  • A smooth surface is able to create a strong echo when hit by sound waves and act like a mirror when hit by light waves.
  • A rough surface will scatter sound and light waves in all directions.
  • The image produced in a reflection is virtual, upright and laterally inverted.
  • Sound waves are longitudinal and need to travel through a medium.
  • The greater the amplitude the louder the sound.
  • The greater the frequency the higher the pitch.
  • The range in which wavelengths occur are represented on the electromagnetic spectrum.
  • Radio waves are what people use to transmit radio and television programmes.
  • Diffraction means that radio waves are able to travel past obstructions like hills.
  • Very low frequency waves are also reflected from the ionosphere.
  • Microwave transmitters and receivers, which are located on masts and various buildings, are able to communicate with mobile telephones but only within their range.
  • Microwave radiation travelling at particular wavelengths are able to travel out of the Earth’s atmosphere and are used to communicate with satellites orbiting in space.
  • Visible light is a very useful way of communicating through, for example, literature, photography or video.
  • It’s not possible for humans to see infra red radiation but it can be felt as heat energy.
  • Scientific evidence suggests that the universe is currently expanding.
  • It’s thought that the universe began as one very small point then, about 13.7 billion years ago, this point suddenly enlarged rapidly in a hot explosion or a ‘big bang’.
  • The Doppler effect is where there’s a change in both frequency and wavelength.
  • It’s been discovered that the further away a star is from Earth the larger the red-shift in its light so we can conclude that everything in the universe is moving away from everything else.
  • Cosmic microwave background radiation (CMBR) is thought to be energy left after the Big Bang.