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Science

Uses of radioisotopes

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Background radiation released by soil, rocks and cosmic rays is always in the environment.

Radioisotopes are used as tracers in medicine and industry. Carbon-14 is a radioactive isotope of carbon, which is found in all living organisms. We can estimate the age of dead organisms by measuring the amount of carbon-14 left in them.

Artificial radioactivity

There's always background radiation in the environment in the form of alpha particles, beta particles and gamma rays.

Background radiation

Most is released by radioactive substances in soil and rocks and cosmic rays from outer space.

Natural background radiation

SourceType of radiation

Cosmic radiation

Cosmic rays

Radiation that reaches the Earth from outerspace

A cow

Animals

All animals emit natural levels of radiation

Some rocks

Rocks

Some rocks give off radioactive radon gas

A plant

Soil and plants

Radioactive materials from rocks in the ground are absorbed by the soil and hence passed on to plants

Higher tier only

Not all background radiation occurs naturally. A small amount is caused by humans.

Non-natural background radiation

SourceType of radiation

Radiation from nuclear missiles

Nuclear Missiles

Nuclear bombs have been exploded by humans, releasing radiation into the environment.

Radiation from x-rays

X-rays

A form of radiation we encounte when we travel by air or have a chest x-ray in a hospital.

Radiation from nuclear power plants

Nuclear power

Nuclear power stations have released radiation into the environment

The pie chart below shows proportions of man made background radiation:

50% radon gas from the ground, 12%  buildings and the ground, 12% food and drink, 12% cosmic rays, 14% artificial sources - mainly cosmic rays, small amount of nuclear power and weapons test

Average contribution of different sources to natural background radiation

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