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Hazards of radiation
Radiation and living cells
When radiation collides with molecules in living cells it can damage them. If the
DNA in the nucleus of a cell is damaged, the cell may become cancerous. The cell
then goes out of control, divides rapidly and causes serious health problems.
Radiation warning symbol
The greater the dose of radiation a cell gets, the greater the chance that the cell
will become cancerous. However, very high doses of radiation can kill the cell
completely. We use this property of radiation to kill cancer cells, and also harmful
bacteria and other micro-organisms.
The hazard symbol is shown on containers of radioactive substances to warn of
Alpha, beta and gamma radiation
The degree to which each different type of radiation is most dangerous to the
body depends on whether the source is outside or inside the body.
If the radioactive source is inside the body, perhaps after being swallowed or
Alpha radiation is the most dangerous because it is easily absorbed by cells.
Beta and gamma radiation are not as dangerous because they are less likely to be
absorbed by a cell and will usually just pass right through it.
If the radioactive source is outside the body:
Alpha radiation is not as dangerous because it is unlikely to reach living cells inside
Beta and gamma radiation are the most dangerous sources because they can
penetrate the skin and damage the cells inside.
Notice that these effects are opposites and make sure you get them the right way