Once light has been produced it will keep travelling in a straight line until it hits something else. Messages wouldnt get very far since sound waves cant travel in the vacuum of space. Sound Waves And Electromagnetic Waves Ppt Download Science Notes Sound Waves Physics Lessons Light travels in straight lines. . 1221 SOUND NEEDS A MEDIUM TO TRAVEL Sound is a mechanical wave and needs a material medium like air water steel etc. The mechanical vibrations that can be interpreted as sound can travel through all forms of matter. Since sound vibrations can travel through the air ground water and any form of medium defense by using physical barriers is difficult. The vibrations can also affect at a molecular level. So theyre totally different scales. Light can travel through empty space. A wave model of light is useful for explaining brightness color and the frequency-dependent bending of light at a surface betwe