How does the speed of waves vary in different media? radio waves are used to transmit verbal messages through space. sound waves are transferred by the compression of particles. the closer the particles are to one another, the faster the energy is transferred. i hear the train coming! i will hear the train through the air before i feel the vibration in the tracks. as a wave travels into a medium in which its speed increases, its wavelength would stay the same. the denser the medium, the slower the speed of a light wave.