GCSE · Physics · AQA · Spec 8463

Background radiation (physics only)

Right now there's radiation all around you — and nothing has gone wrong. So where does it come from? Most people's first guess misses half the answer.

Physics · Background radiation

Natural or man-made?

Each of these is a source of background radiation. Did it come from nature, or from something people did?

Still to sort

Natural (0)

Part of the natural world — nobody made it.

Where the line is: Ask yourself: would this source be there if people had never done anything? If yes, it's natural.

Man-made (0)

Only exists because of something people did.

Where the line is: If the source only exists because of human activity, it's man-made.

4 of 4 still to sort.

Pick a source, then choose the group it belongs in.

What does 'background' really mean?

Be honest — which is closest to what you think?

A friend says: "Background radiation? That's the stuff you get after a nuclear accident, isn't it?"

Which of these is closest to what you think right now?

Background radiation only exists where something has gone wrong — like a nuclear accident or a weapons test.All background radiation is made by people. Nature doesn't give off radiation.It's around us all of the time, and it comes from both natural and man-made sources.It's only around some of the time — it comes and goes, like weather.

How sure are you?

I'm sureI think soI'm guessing

Background radiation only exists where something has gone wrong — like a nuclear accident or a weapons test.

This is a common misconception

Nuclear accidents and weapons testing are real sources — but they're only part of the story. Background radiation is around us all of the time. Nothing has to go wrong for it to be there, because natural sources such as rocks and cosmic rays from space are part of it too.

All background radiation is made by people. Nature doesn't give off radiation.

This is a common misconception

This is the idea the sort above was built to catch. Background radiation has natural sources as well as man-made ones: rocks and cosmic rays from space are natural. If people had never done anything nuclear, those natural sources would still be there.

It's around us all of the time, and it comes from both natural and man-made sources.

This matches the evidence

Spot on. Background radiation is always around us. Some comes from nature (such as rocks and cosmic rays from space) and some comes from people (such as fallout from nuclear weapons testing and nuclear accidents).

It's only around some of the time — it comes and goes, like weather.

This is a common misconception

The word 'background' is the clue here. Background radiation is around us all of the time — it's the radiation that's always there in the background, not something that switches on and off.

Background radiation never goes away: it's around us all of the time, from natural sources and man-made sources.

Predict, then check

Background radiation is around everyone. But does that mean everyone gets the same amount?

Two people are alike in every way except one: they do different jobs. Must they receive the same level of background radiation and the same radiation dose?

Physics · Radiation dose

One dose, two units

Dose: 4/8. In millisieverts 1000 mSv. In sieverts 1 Sv

In millisieverts1000 mSvIn sieverts1 Sv

Radiation dose is measured in sieverts (Sv). Drag along the bar: the two readings always describe the same dose, written in two different units. These are practice numbers only — not the dose from any real source, job or place.

Your turn

Say it in your own words

Background radiation is around us all of the time. Name one natural source and one man-made source of background radiation, and give one thing that may affect the radiation dose a person receives. [3 marks]

Your answer

0 words · your answer stays on this page and is not sent anywhere.

The mark scheme

One natural source: rocks, or cosmic rays from space. (1 mark)
One man-made source: fallout from nuclear weapons testing, or nuclear accidents. (1 mark)
One factor: occupation (the job someone does) or location (where they are). (1 mark)

Model answer

A natural source is cosmic rays from space. A man-made source is fallout from nuclear weapons testing. A person's radiation dose may be affected by their occupation.

One source from each group, named precisely, plus occupation or location. Keep the word 'may' — those factors can affect a dose; they don't always change it.

WHAT YOU'VE LEARNED

A quick recap of today's lesson.

It's around us all of the time. Some of it comes from nature, some from people — and we measure the dose in sieverts.

What you need to know

Background radiation is around us all of the time.
It comes from natural sources, such as rocks and cosmic rays from space.
It also comes from man-made sources, such as fallout from nuclear weapons testing and nuclear accidents.
A person's level of background radiation and radiation dose may be affected by their occupation and/or location.
Radiation dose is measured in sieverts (Sv): 1000 millisieverts (mSv) = 1 Sv.

The big picture

Background radiation is radiation that is around us all of the time. It comes from natural sources, such as rocks and cosmic rays from space, and from man-made sources, such as the fallout from nuclear weapons testing and nuclear accidents. The level of background radiation, and the radiation dose a person receives, may be affected by their occupation and/or their location. Radiation dose is measured in sieverts (Sv), and 1000 millisieverts (mSv) = 1 Sv.

Key points

1'Background' means always there — no accident is needed for background radiation to exist.

2Natural sources: rocks and cosmic rays from space. Man-made sources: fallout from nuclear weapons testing and nuclear accidents.

3Always there doesn't mean the same for everyone: occupation and/or location may affect the level and the dose.

41000 mSv = 1 Sv. Sv → mSv: multiply by 1000. mSv → Sv: divide by 1000.

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Worked example

Problem

A radiation dose is given as 7.5 mSv. Write this dose in sieverts (Sv).

⚠ Watch out

Converting the wrong way. Going from mSv to Sv, some people multiply by 1000 and end up with a huge number. A sievert is the bigger unit, so the same dose in Sv is always the SMALLER number — divide by 1000.

🧠

Memory hook

Nature gives us Rocks and Rays; people added Tests and Accidents. And 'milli' means a thousandth: 1000 mSv make 1 Sv.

✓

Check yourself

Cover the page. Sort the four sources into natural and man-made, say what may affect a person's dose, then turn 0.03 Sv into mSv. (30 mSv — multiply by 1000.)

Flashcards

(11)

What is background radiation?

Radiation that is around us all of the time.

Name two natural sources of background radiation.

Rocks, and cosmic rays from space.

Name two man-made sources of background radiation.

Fallout from nuclear weapons testing, and nuclear accidents.

Does background radiation only exist after something goes wrong, like a nuclear accident?

No. It's around us all of the time — natural sources such as rocks and cosmic rays from space are always part of it.

Fallout from nuclear weapons testing: natural or man-made? Why?

Man-made — it only exists because people tested nuclear weapons.

What two things may affect a person's level of background radiation and their dose?

Their occupation and/or their location.

Background radiation is around everyone. Does that mean everyone gets the same dose?

Not necessarily — occupation and/or location may affect the dose.

How many millisieverts (mSv) make 1 sievert (Sv)?

1000 mSv = 1 Sv.

What does 'milli' mean in millisievert?

A thousandth: 1 mSv is one-thousandth of a sievert, or 0.001 Sv.

Converting a dose from mSv to Sv: multiply or divide by 1000?

Divide by 1000 — the sievert is the bigger unit, so the number gets smaller.

Radiation dose is measured in sieverts (Sv). Write 2 Sv in mSv.

2000 mSv (Sv to mSv, so multiply by 1000).

Tap any card to flip it, or use Study as deck to go through them one at a time. In the full lesson these run as a spaced-repetition deck — you rate each card Hard, Good or Easy and the tricky ones keep coming back until they stick.

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Background radiation (physics only)

Natural or man-made?

Be honest — which is closest to what you think?

Say it in your own words

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