Radiation is found naturally all around us in background radiation from sources like rocks, buildings, food, and drink. Certain rocks contain radioactive elements like radon that produce ionizing radiation, which can damage living cells by leaving them unaffected, slightly damaged but self-repairing, causing DNA damage and cancer, or causing cell death. The average yearly radiation dose a person in the UK receives is about 3 millisieverts, which measures the amount of radiation exposure. Irradiation occurs when a radiation source is outside the body, while contamination is when the source enters the body.

1. Lesson 2: Radiation everywhere
What you need to know:
1. Sources of radiation can be found all around us.
2. You are exposed to radiation, called your radiation dose.
Radiation can be found all around you. It occurs naturally from objects such as
rocks, buildings, food and drink and this is called background radiation.
In your exam you may be asked to explain what background radiation is.
Certain rocks can naturally contain a radioactive element called Radon. Radon is
radioactive, which means that it produces ionizing radiation that could be
harmful to living cells. Ionizing radiation can affect living cells in different ways:
1. The cell is unaffected.
2. The cell is slightly damaged but fixes itself.
3. The cell’s DNA can be damaged, leading to cancer.
4. The cell dies
In your exam you may be asked how ionizing radiation can affect living cells.
A radiation dose is how much radiation a human is exposed to every
year. A radiation dose is measured in millisieverts (mSv) and the average UK
dose is approx 3 mSv.
If you are exposed to a source of radiation which is outside your body, then
this is called irradiation. If the source of radiation gets into your body, then
this is called contamination.
In your exam you may need to know the difference between irradiation and
contamination.
Recap:
1. Radiation is all around us and this is called background radiation.
2. Any object that emits ionizing radiation is called radioactive.
3. A radiation dose is the amount of radiation a human is exposed to every year.
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