Give a physical description of radio waves and compare and contrast it with the frequency, wavelength, energy and wave speed with those of other regions of the EMS.

There is nothing physical about radio waves. They are pulses of energy caused by periodic variations in electric and magnetic fields. These are caused by electrons “jumping” between energy levels. Radio waves have the lowest energy, longest wavelengths and lowest frequencies. These values change gradually as we go through microwaves, infra red, visible light, ultra violet, x-rats abd gamma rays which have the highest energy, highest frequency and shortest wavelength.

The independent variable would be the fertilizer as it is what the dependent variable (the growth of grass) depends on.