Light can be described as a wave or a particle. As a wave, light is made up of oscillating electric and magnetic fields that propagate as electromagnetic waves. Electromagnetic waves include radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays. Visible light is a small portion of the electromagnetic spectrum. As a particle, light exists as discrete packets of energy called photons, with the energy of each photon depending on the wavelength and frequency of the electromagnetic wave.