In the world around us we can find many examples very similar to harmonic vibrations: a point on the string of a guitar after plucking it, the tremor at the end of a sheet of metal when it is struck... In all of these there are common characteristic magnitudes. These magnitudes are going to play an important role in our understanding of waves.

In the following visual we will try to study them, not with a spring or a similar example, but with a particle subject to a harmonic vibration for causes which are not of interest at the moment. We are just interested in knowing the magnitudes which describe this movement and some relations among them.