Simulation of Nuclear decay
Simulation Overview
Three tabs show alpha, beta, and gamma nuclear decay at the atomic level. Each opens with an unstable nucleus — protons (red) and neutrons (blue) packed together and shaking furiously inside a glowing boundary ring, surrounded by four bright electron shells. At the moment of decay the nucleus instantly settles still, and the emitted particle flies outward. The nuclear equation is shown below each animation with a Replay button.
- α tab — Ra-226 ejects a gold helium-4 nucleus (2p+2n), daughter Rn-222 recoils left
- β tab — C-14 flashes as a neutron converts to a proton, then fires an electron and antineutrino
- γ tab — Excited Tc-99m* pulses, then releases an expanding gamma wave in all directions; composition unchanged
Class Activity — “Spot the Difference” (10–15 min, KS4 pairs)
Students open all three tabs in sequence and complete a quick comparison table:
| Alpha | Beta | Gamma | |
|---|---|---|---|
| What is emitted? | |||
| Does A change? | |||
| Does Z change? | |||
| Nucleus stable after? |
Discussion questions:
- All three nuclei shake before decay — what does this tell us about unstable nuclei?
- In gamma decay the nucleus looks the same before and after — why?
- Why does the antineutrino in beta decay appear almost invisible?
Exit question: Ra-226 undergoes alpha decay. Write the nuclear equation and state what happens to A and Z. Expected: A decreases by 4, Z decreases by 2, daughter is Rn-222.