Radioactive Decay & Half-Life

—

About this simulation

Watch individual nuclei decay unpredictably while the whole sample follows a statistical pattern. Compare small and large samples.

What students can explore

What fraction is expected after one, two and three half-lives? Must every sample match it exactly?
Each nucleus receives an independent exponential lifetime. N=N₀×2^(−t/T½) is the expected curve. Circles are undecayed parents; crosses are daughters assumed stable. Time units and isotope are illustrative. New sample changes the random seed; reset repeats the original sample.

Learning objectives

1What fraction is expected after one, two and three half-lives? Must every sample match it exactly?

Questions teachers ask

What fraction is expected after one, two and three half-lives? Must every sample match it exactly?

The expected fractions are 1/2, 1/4 and 1/8. Random samples differ; proportional fluctuations are usually larger for small samples.

About the model

Each nucleus receives an independent exponential lifetime. N=N₀×2^(−t/T½) is the expected curve. Circles are undecayed parents; crosses are daughters assumed stable. Time units and isotope are illustrative. New sample changes the random seed; reset repeats the original sample.

Embed this simulation

Drop it into your LMS, blog, or class site — free.

<iframe src="https://kiwibee.io/en/simulations/radioactive-decay-half-life-simulation/embed" title="Radioactive Decay &amp; Half-Life | KiwiBee" loading="lazy" allowfullscreen style="width:100%;height:min(70vh,620px);min-height:420px;border:0;border-radius:16px"></iframe>

Continue exploring

Explore an adult male reference body in 3D. Reveal 14 anatomical systems, search thousands of named structures, isolate organs, and pull 2,209 modeled pieces apart to see how the body is organized.

—

Explore the head and neck in 3D: 643 source meshes across 14 layers, 47 facial and masticatory muscles, and 77 drawn nerves, vessels and glands the source scan omits. Open any tooth onto its own pulp canal, and follow the seven stages of tooth development.

—