Types of Radiation

Ever wondered why smoke detectors work or how doctors treat cancer? Radiation is the answer, and understanding its three types will help you grasp some pretty cool science.

Alpha radiation is basically a helium nucleus - that's 2 protons and 2 neutrons flying about. It's the weakest traveller of the bunch, only making it 5-10 cm through air before getting stopped by something as thin as paper. However, don't underestimate it - alpha has the highest ionising ability, meaning it's brilliant at knocking electrons off atoms when it hits them.

Beta radiation consists of fast-moving, high-energy electrons shot out from the nucleus. These particles are proper middle-of-the-road types - they've got moderate penetrating power and moderate ionising ability. You'd need thin aluminium to stop them, and they can travel about a metre through air.

Gamma radiation is the superhero of the radiation world. As high-energy electromagnetic radiation, it has unlimited range in air and the highest penetrating ability - you need thick concrete or lead to stop it. Ironically, it has the lowest ionising ability, but that makes it perfect for sterilisation and cancer treatment since it can reach deep into materials without causing too much damage along the way.

Quick Tip: Remember the pattern - as penetrating ability increases (alpha → beta → gamma), ionising ability decreases!