Particles: an interactive particle physics course

Particles is an interactive particle physics course that zooms from an atom down to quarks and out to the Standard Model. Its 23 short sections cover protons, neutrons and electrons, quarks and their six flavours, leptons, the four forces and their carrier particles, beta decay, the Standard Model, antimatter, annihilation and pair production, baryons and mesons, the Higgs boson, and how accelerators and detectors find it all.

It opens by zooming from a helium atom into its nucleus, then into a proton and a neutron, adding up the charges at each level, which is exactly the habit the course builds.

What the particle physics course covers

Matter particles

Protons and neutrons are made of quarks: a proton is up, up, down and a neutron is up, down, down. With an up quark carrying +⅔ and a down −⅓, the proton's charge comes out as +1 and the neutron's as 0. Quarks come in six flavours across three generations, and leptons, the electron's family, in six more.

Forces and the Standard Model

Particles feel forces by exchanging carrier particles: photons for electromagnetism, gluons for the strong force, and W and Z bosons for the weak force, which can change one quark flavour into another, as in beta decay. Together with the Higgs boson, these make up the 17 fundamental particles of the Standard Model.

Antimatter and experiments

Every particle has an antiparticle with the same mass and opposite charge. When they meet they annihilate into energy, and enough energy can create a particle and antiparticle pair. The final sections show how accelerators speed particles up with electric fields and steer them with magnets, and how layered detectors identify what comes out of a collision.

Try a question from the course

Each particle in an atom has a fingerprint. A proton has charge +1 and a relative mass of 1, and sits in the nucleus. A neutron also sits in the nucleus with relative mass about 1, but has no charge. An electron has charge −1 and a tiny mass, about 1/1,840 of a proton's, and sits outside the nucleus. So "no charge, found in the nucleus" means a neutron.

Now identify a particle from a new description, then press Mark to check your answer in the course.

Who this course is for

• A-level and other advanced physics students studying particles, quarks, antimatter and exchange particles.
• GCSE students who want to see what lies beyond the atomic model.
• Curious learners who have heard of the Large Hadron Collider and the Higgs boson and want to know what they are about.

What you need to know first

The course page suggests Light & Energy first, because photons and E = hf come up again here. You need to be happy adding fractions for quark charges and using standard form for tiny masses and energies. Our specific charge guide uses the same particle data.

How long it takes

There are 23 sections and most take a few minutes. Learners without a plan can open two sections of a course a day, in order, so the whole course takes 12 days. A plan removes the daily limit and lets you go straight to any topic, such as antimatter.

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