Waves

     A wave is a disturbance or oscillation that travels through space and matter.  A wavelength is literally the length of the wave.  A complete wave consists of a trough and a crest.  Waves are things that occur everyday in pretty much everything that we do.  The ocean has waves and it is very to easy to see the different parts of a wave in an ocean wave.  The trough and the crest are noticeable.  Another obvious example of a wave is sound waves.
     There are two types of waves, transverse waves and longitudinal waves.  Transverse waves are waves which the energy of the wave and the energy given off by the wave are perpendicular to each other.  Longitudinal waves are ones which wave energy and the energy from the wave travel parallel to each other.  Sound waves, like ones given off by this speaker, are longitudinal waves.  The reason is that both paths of energy travel in the same direction.