Waves in air, fluids and solids GapFill

Waves are the repeated motion of particles (or fields) around a point, that carry energy from one place to another.
 PolarisedLongitudinalSeismicTransverse waves are waves where the particles oscillate in a direction at right angles to the direction in which the wave transfers energy.
 TransverseLongitudinalPolarisedSeismic waves are waves where the particles oscillate in the same direction as the direction in which the wave transfers energy.
Features of waves include:

•  wave speedfrequencydisplacementwavelength, the number of waves that pass a point every second, which is measured in  joulessecondshertznewtons
•  displacementfrequencywavelengthwave speed, the distance between two corresponding points on a wave
•  wave speedamplitudedisplacementwavelength, the furthest a particle travels from its central point
•  wavelengthdisplacementwave speedperiod, the time taken for a single cycle of a wave to pass a point
•  wave speeddisplacementamplitudeperiod, the rate at which energy is transferred by the wave through a medium

Frequency (f) and period (T) are related by the equation  f = T³f = 1/T²f = √(T)f = 1/T.
Wave speed (v), frequency (f) and wavelength (λ) are related by the equation  v = f/λv = fλv = f²/λv = λ/f.

When a wave meets a boundary between two materials, it can be absorbed, transmitted or reflected. A reflected wave  does not pass through the boundary, and instead travels back into the medium it was originally inchanges speed after passing through the boundarystops travelling once it reaches the boundarychanges wavelength after passing through the boundary.
Sound waves travel as vibrations in the air. Within the ear, this causes  the whole ear to vibratewater in the ear to vibratethe whole ear to become chargedthe eardrum to vibrate, which is converted into a signal which can be interpreted by the brain. Humans can only hear sound waves within a frequency range of around 20 Hz to 20 kHz; frequencies above 20 kHz are known as  infrasoundpseudosoundsubsoundultrasound and this is used in medical and industrial imaging processes.
Earthquakes produce  richter wavesgeological wavesseismic wavesterrestrial waves, which travel through Earth's crust and mantle, and, when detected, can tell us information about where the earthquake originated and the composition of Earth.
Imaging techniques using sound measure  the shape of the wavethe energy of the wavethe intensity of the wavethe time taken between a wave being emitted and detected to determine the distance to the reflecting object or surface.