Radioactive Decay Simulation — Description
Half-Life Simulation
64 radioactive atoms are displayed in a grid. Each atom glows and shakes while unstable. When it decays, it flashes and dims. The live graph on the right plots actual decay data against the theoretical curve N(t) = N₀ · e^(−λt) in real time.
Choose from five AQA isotopes — Carbon-14, Polonium-210, Radium-226, Technetium-99m, Sodium-22. Each has its own colour. Pause and reset at any time.
Key concepts visible:
- Decay is random — atoms pop unpredictably, never in order
- The actual curve (coloured line) follows but never exactly matches the theoretical curve (dashed yellow) — demonstrating statistical variation
- After each half-life, roughly half the remaining atoms decay
Suggested Class Activity (10 min, KS4 pairs)
Task: Watch one full run of Carbon-14. Record the undecayed count at each half-life marker on the graph.
| Half-lives | Predicted | Actual |
|---|---|---|
| 0 | 64 | 64 |
| 1 | 32 | ? |
| 2 | 16 | ? |
| 3 | 8 | ? |
Discussion: Why doesn’t the actual line match the predicted line exactly? Switch to Technetium-99m — does it decay faster or slower? How can you tell from the graph?
Exit question: A sample has 64 atoms. After 3 half-lives, how many remain? Is this guaranteed?