Radioactive Decay and Half-Life: free physics simulation
Watch unstable nuclei decay one by one at random, and see the half-life appear from the chaos.
▶ Open the simulationFree, no sign-up. Works on phones, tablets and laptops.
The science
Unstable nuclei decay at random: every nucleus has the same chance of decaying in a given time, but no one can say which will go next. With many nuclei the randomness averages out into a smooth curve, and the half-life is the time for half of them to decay. This is how carbon dating and medical tracers work.
N = N₀ × (½)^(t / T½)
Things to try
- Let one half-life pass and count how many nuclei are left.
- Compare 100 nuclei with 1600 and see which follows the curve better.
- Switch to uranium-238 and compare its half-life with carbon-14.
Topics covered
radioactivity half life nuclear isotope carbon dating alpha beta gamma random exponential
How to use it
Open the simulation, then change the experiment live with the sliders, checkboxes and buttons in the side panel. Drag objects on screen where it makes sense, and use Pause, Step, Speed and Reset in the bottom bar to study every moment.
Frequently asked questions
What does the Radioactive Decay and Half-Life simulation show?
Unstable nuclei decay at random: every nucleus has the same chance of decaying in a given time, but no one can say which will go next. With many nuclei the randomness averages out into a smooth curve, and the half-life is the time for half of them to decay. This is how carbon dating and medical tracers work.
What is the key equation?
N = N₀ × (½)^(t / T½)
Is the Radioactive Decay and Half-Life simulation free?
Yes. It runs free in any web browser on phones, tablets and laptops, with no sign-up or download.
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