• Question: why is sound faster then light??

    Asked by 07rowleys to Hywel, Keith on 25 Jun 2010 in Categories: .
    • Photo: Hywel Vaughan

      Hywel Vaughan answered on 25 Jun 2010:

      I’m afraid to say that sound isn’t faster than light rowley – it is in fact the other way around. Light travels at approximately 671 million miles per hour. The speed of sound however varies depending on the density of air you are at and what temperature it is – at a temperature of 15 degrees C the speed of sound is approximately 761.2mph at sea level.

      The reasons why light is faster than sound is a little more complex… Light is an electromagnetic wave (the same as radio, TV, infrared etc) whereas sound is a pressure wave – it only becomes ‘sound’ when it enters your ear and causes your eardrums to vibrate.
      Sound cannot travel without a medium (something to travel in – i.e cannot operate in a vacuum), because it depends on physical vibration, whereas light can and does travel in a vacuum. Quite simply, sound relies on the movement of particles, whereas light does not 🙂

    • Photo: Keith Brain

      Keith Brain answered on 25 Jun 2010:

      Mostly, its the other way around – that light is faster than sound.

      Sound involves the movement of particles, like the molecules in the air. These molecules have inertia (which means that they don’t want to move unless you push them hard enough), so sound it slower because it takes time for the molecules to move and bang into one another. With light, however, no mass needs to move – its all about electric and magnetic fields, which can travel through space very quickly.