Inside the Proton

Quarks

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Protons (uud) and neutrons (udd) are made of up and down quarks.
• Up: +2/3, down: −1/3. Quarks are always confined inside composite particles.
• The weak force can change a quark’s flavour, as in beta decay.

Steps

1. Smaller still
2. Up and down quarks
3. A strange particle
4. Build a baryon
5. A quark and an antiquark
6. Beta decay, deeper