The different names refer to different wavelengths, as shown in the demo below. Use the
mouse to move the slider and change the wavelength. Drawings are not to scale.
I know what water waves are, but here there is no water! So
what's the wave made of?
The wave, or "disturbance," is in an invisible thing called the electric force field. To
understand electric forces, we have to learn something about charged particles like
electrons and protons. Without these charged particles, there can be no electric force
fields and thus no electromagnetic waves.