Chemistry • Nuclear Science Investigation

Nuclear Decay Lab

Observe alpha, beta-minus, and gamma decay, balance nuclear equations, compare shielding, and model the random nature of radioactive half-life.

α • β⁻ • γNuclear equationsShielding testRandom half-life
A

Nuclear event viewer

Protons and neutrons are shown schematically, not to physical scale.

Parent—
Daughter—
Change in A—
Change in Z—
Emitted—
3

Shielding investigation

Compare the penetrating ability of α, β, and γ radiation.

αsource
No shield
Detector100%

Detector percentages are a conceptual comparison only. Real attenuation depends strongly on radiation energy, material, and thickness.

4

Half-life sample

Compare a smooth theoretical curve with random decay of individual nuclei.

Elapsed time0.0 half-lives
Parent nuclei remaining—
Fraction remaining—
Expected value—
5

Half-life graph

A half-life predicts the behavior of a large sample, not the exact decay time of one atom.

Parent nuclei remaining

Random samples fluctuate around the theoretical exponential decay curve.

Alpha decay

Emits a helium nucleus: A decreases by 4 and Z decreases by 2.

Beta-minus decay

A neutron changes to a proton while an electron is emitted: A stays the same and Z increases by 1.

Gamma decay

An excited nucleus releases electromagnetic energy: neither A nor Z changes.

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