The electromagnetic spectrum includes all types of radiation that travel at the speed of light and then spread out. In order of wavelength, from longest to shortest, the electromagnetic spectrum includes--radio waves, microwaves, infrared, visible light, ultraviolet light, Xrays and gamma rays. The radio waves have low energy, longer wavelength and lower frequency and gamma rays have high energy, shorter wavelength and higher frequency. Sound occurs when a vibration is carried through a medium-solid, liquid or gas. A vibrating body can generate sound waves. For example, if someone's vocal cords vibrate, and the air around them vibrates, this creates sound--and we hear speech when the eardrum, ear bones and fluid in the cochlea all vibrate and create a nerve impulse which is recognized by the brain as sound. Radio waves are different from sound waves.