Chemistry · Virtual lab
Rutherford's α-Particle Scattering
Fire α-particles at a thin gold foil, count where they scatter, and discover the tiny dense nucleus at the centre of the atom.
Background
In 1911 Ernest Rutherford directed a beam of α-particles (helium nuclei) at a thin gold foil and observed their scattering pattern. Most particles passed straight through, but a small fraction were deflected at large angles, and a few even bounced back. This was incompatible with Thomson's "plum pudding" model of the atom.
Rutherford concluded that the positive charge and nearly all the mass of an atom are concentrated in a tiny, dense nucleus, while electrons orbit in the mostly empty space around it. This nuclear model of the atom became the foundation of modern atomic physics.
In this virtual lab you fire α-particles at a gold foil, count the scattered particles at different angles using a movable zinc-sulphide screen, and use the scattering data to deduce the existence and size of the nucleus.
What you will learn
- Set up the α-particle source, gold foil, and detector
- Observe scattering at various angles
- Analyse the distribution of scattered particles
- Understand how the results disprove the plum-pudding model
Ready to try this experiment?
Sign in to launch the full interactive 3D simulation, or request a free demo for your school.
Related experiments
- Thomson's Cathode Ray Tube Experiment: Deflect a cathode ray with electric and magnetic fields, balance the two forces, and measure the charge-to-mass ratio of the electron.
- Millikan's Oil Drop: Catch a charged oil drop, weigh it by timing its fall, and find the charge of the electron as the smallest step every droplet is a multiple of.