This memory aid covers Memory Aids within Radioactive Decay for GCSE Physics. Revise Radioactive Decay in Atomic Structure for GCSE Physics with 15 exam-style questions and 6 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 10 of 14 in this topic. Use it for quick recall, then test yourself straight afterwards so the memory aid becomes usable in an answer.
🧠 Memory Aids
Penetrating power order: "Paper, Aluminium, Lead" — PAL. Alpha blocked by Paper, Beta by Aluminium, and Lead is needed for gamma (though it still gets through to some extent).
What changes in each decay:
- Alpha: A goes down 4, Z goes down 2 (loses a "he-4" helium nucleus)
- Beta: Z goes up 1, A stays same (neutron becomes proton: +1 proton)
- Gamma: Nothing changes in nucleus (just energy release)
Ionising vs penetrating: Think of a charging rhinoceros vs a laser beam. The rhino (alpha) does massive damage but stops quickly. The laser beam (gamma) pierces through everything but doesn't do much damage at each point.
Practice questions for Radioactive Decay
An alpha particle consists of which particles?
Explain why alpha radiation is described as highly ionising but weakly penetrating.