Physics education class on electromagnetic waves, frequency & wavelength FREE science lesson: How water waves, sound waves and light waves are all similar? They can all be described in terms of their wavelength, frequency, amplitude and speed. Each of these parameters are defined so that science students can see clearly what they mean, and how they are measured. The famous German scientist Heinrich Hertz is discussed. Simple harmonic motion is also introduced and a couple of examples are shown. The difference between the motion of the wave and the motion of the medium is clarified.