• Question: Are laser beams always dangerous? Can they be constructive? Thanks!

    Asked by shoetree3 to Mike, Pip, Tianfu, Tim, Tom on 28 Jun 2012.
    • Photo: Tom Lister

      Tom Lister answered on 28 Jun 2012:

      They are rarely dangerous but are used in all sorts of applications, from reading CD and DVDs, to measuring distances when making maps, or some of the cool things these other scientists are doing.

      The lasers I use are dangerous, but we only use them for nice things.

    • Photo: Tim Stephens

      Tim Stephens answered on 28 Jun 2012:

      Not always. It depends on how much power the laser beam has. There’s a classification scheme that gives you an idea of how safe a laser is.
      It goes from Class 1 which is completely safe to Class 4 which is powerful enough to cause injury or damage.
      Incidentally, I think that the actual laser in a CD player is quite powerful, but it’s completely safe to you and me because it’s locked away inside the machine. If you open the drawer, the laser is turned off. I saw some guys on the internet made a laser cutter out of the laser from a CD player.

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