• Question: why cant x-rays examine past lead?

    Asked by marshmallowfluff to Adam on 20 Nov 2013.
    • Photo: Adam Murphy

      Adam Murphy answered on 20 Nov 2013:

      Hey, cool question Radiation is something really interesting!

      It’s not that it’s lead that stops them, you can do it with concrete walls or big stone walls. It’s just that lead is really heavy and dense.

      X-Rays are light rays that our eyes can’t see, kind of like UV light, but with a lot more energy. What you need to do is put a whole load of stuff in the way of the X-Ray to absorb it. So you just need something big, thick and heavy. The atoms there slowly eat away at the X-Ray until there’s nothing left at the other side to detect! This is true for Gamma Rays as well, which are another type other radiation made from light rays (X-Rays and Gamma Rays are very very similar.)

      There are two other kinds of radiation, Alpha and Beta radiation, which are made of particles. If they get inside you they can be really, really dangerous, but usually your skin is thick enough to stop them.

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