What can I see on the electromagnetic spectrum?
This is a quite difficult question indeed...
To keep it short you can see all the possible waves produced when you have a perturbation of the electro-magnetic field .
You can start from RADIO waves produced by accelerating a charge on a antenna (long wavelength and low frequency) or you can see GAMMA RAYS produced in nuclear reactions (very short wavelength and very high frequency).
In the middle you have a lot of well known waves as...
VISIBLE (the light we see)
MICROWAVES (the one you use to cook)
X-RAYS (the dentist uses them to "see" your teeth)
UV (you get them on the beach)
IR (from fires and hot stuff)
Ok, probably is not a lot but I hope it helps!