Physics » Waves

Waves

Key Words

Waves transfer energy in the direction they are travelling.

Amplitude - maximum displacement of a point on the wave.

Wavelength - distance between the same point on two adjacent waves.

Frequency - the number of complete waves passing a certian point per second.

Hertz (Hz) - the measurement of frequency.

Oscillations - vibrations.

Transverse waves - the oscillations travel up and down.

Longitudinal waves - the oscillations in the same direction as the wave travels.

Waves can be:

  • Absorbed - this transfers energy to the material's energy stores.
  • Transmitted - waves travel thorugh the new material.
  • Refraction -waves cross a boundary between materials, the angle is changed.

Specular reflection - wave is reflected in a single direction.

Diffuse reflection - wave is reflected by a rought surface and scattered in different directions.

Sound waves - caused by vibrating objects.

Parts of the ear:

  • Ear drum - vibrates as sound waves reach.
  • Ossicles - receive the vibrations from the ear drum.
  • Cochlea - turns vibrations to electrical signals which then get sent to your brain.

Ultrasound - sound with frequencies higher than 20,000Hz.

Echo sounding - used by boats and submarines, use high-frequency sound waves including ultrasound.

Seismic waves - produced by earthquakes which out through the Earth.

Seismometers - detect seismic waves over the surface of the planet.

Seismologists - study seismic waves to work out the time it takes for the shock waves to reach each seismometer.

P-waves - longitudinal waves that travel through solids and liquids and speeds faster than S-waves.

S-waves - transverse waves that can't travel through liquids or gases.

Also see Electromagnetic Waves, Light,

 

PRACTICAL Waves in a ripple tank

Watch the video and have a go at writing out the steps of the practical.

Note paper for practical