The main danger
from radioactivity is the damage it does to the cells
in your body.
Most of this damage is due to ionisation
when the radiation passes, although if levels of radiation
are high there can be damage due to heating effects
as your body absorbs the energy from the radiation,
rather like heating food in a microwave oven. This is
particularly true of gamma rays. |
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Wrong! Whilst they cannot penetrate
your skin, you could easily eat or drink something contaminated
with an  source.
This would put a source of alpha particles inside your body,
wreaking havoc by ionising atoms
in nearby cells.
If this happens to part of the DNA in one of
your cells, then that cell's instructions about how to live
and grow have been scrambled. The cell is then likely to do
something very different to what it's supposed to do, for
example, it may turn cancerous and start multiplying uncontrollably.
Thus alpha particles, whilst they have a low
penetrating power, can be the most dangerous because they
ionise so strongly. |
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 particles
have a longer range than alphas, but ionise much less strongly,
with the result that they do around 1/20th of the damage done
by the same dose of alpha particles.
However, they do have more penetrating power,
which means that they can get through your skin and affect
cells inside you. |
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rays hardly ionise atoms at all, so they do not cause damage
directly in this way.
However, gamma rays are very difficult to stop,
you require lead or concrete shielding to keep you safe from
them. When they are absorbed by an atom, that atom gains quite
a bit of energy, and may then emit other particles. If that
atom is in one of your cells, this is not good!
You can read more about gamma rays in the Electromagnetic
Spectrum web site. |
Let's see how much you've learned:
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