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| Most of the radioactivity you are normally exposed to is
from natural sources. |
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In fact, you've
grown up on a planet which has, in places, quite a high level of
background radiation, and life on Earth has evolved to cope
with this. Your cells have self-repairing mechanisms which allow
them to survive relatively unscathed.
The amount of
background radiation varies considerably around Britain, as shown
on the map. You can see that it is particularly high in Cornwall,
because of the types of rock there.
Click
to find out about units |
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Background
radioactivity
is
mainly natural radioactivity, all around us. As you can see from
the pie chart, the vast majority of our annual dose comes from radon
gas, food & drink, the ground, and cosmic rays (which are gamma
rays coming in from space).
Unless you are
having radiotherapy,
your dose from medical sources is quite low. The chart also shows
that the nuclear industry adds very little to the level of background
radioactivity.
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Many people
don't realise that your radiation dose from cosmic rays is increased
considerably if you fly a great deal. This is because our atmosphere
provides some protection against cosmic rays, so the higher you
fly the more you get.
However, don't worry - this only tends to be a problem if you're
an airline pilot or an astronaut.
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Now let's see how much you've learned.

This site is designed
to be viewed at 800 x 600 resolution, with level 4 browsers or better.
Created by Andy Darvill, www.darvill.clara.net,Science
teacher at Broadoak Community
School, Weston-super-Mare, England
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