# Ionising radiation and safety

Alpha, beta and gamma can knock electrons off atoms (ionisation), which can damage cells and cause cancer. Safe handling means limiting time, keeping distance and using shielding.

Physics (school) · Part 08: Atoms and radioactivity · Card 6 of 8 · Last updated 2026-10-19

## Analogy

Like standing near a campfire: further away, shorter time and a screen all help.

## In practice

Radiographers wear badges that record how much radiation they have received.

## Practice

### Flashcards

- **Name one safety rule when handling radioactive sources.** Limit the time, keep your distance or use shielding.

### Interview questions

**Compare alpha, beta and gamma radiation in terms of what they are and how far they penetrate.**

- Alpha is a helium nucleus, stopped by paper
- Beta is a fast electron, stopped by thin aluminium
- Gamma is an electromagnetic wave, reduced by thick lead
- Alpha is most ionising and gamma least

## Questions people ask

### How can people protect themselves from radiation?

Reduce the time exposed, stay as far away as possible and use shielding such as lead or thick concrete. Sources are kept in lead-lined containers and handled with tongs. Workers wear badges that record their exposure so it can be checked against safe limits.

### What is the difference between irradiation and contamination?

Irradiation is exposure to radiation from a source outside you, and it stops when the source is removed. Contamination means radioactive material gets onto or into you, so you keep being exposed. Contamination is usually more dangerous because you cannot move away from it easily.

## Related concepts

- [Alpha, beta and gamma](https://studyvisually.com/learn/science/physics-school/physics-school-part-8/physics-school-part-8-concept-4)
- [Radioactive decay](https://studyvisually.com/learn/science/physics-school/physics-school-part-8/physics-school-part-8-concept-3)
- [Half-life](https://studyvisually.com/learn/science/physics-school/physics-school-part-8/physics-school-part-8-concept-5)

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