Half-Life

Random, yet predictable

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Each nucleus decays at random, but large samples follow a smooth half-life curve.
• $N = N_0 (\tfrac12)^{t/T_{1/2}}$: after $n$ half-lives, $\frac{1}{2^n}$ remains.
• Match the half-life to the timescale: carbon-14 for archaeology, uranium for rocks.

Steps

1. Which atom next?
2. Watch them decay
3. Three half-lives
4. Carbon dating
5. Find the half-life
6. Dating rocks