Quantum chromodynamics

Quantum chromodynamics, or QCD for short, is a type of science about how particles, called quarks, interact with each other. Quarks are really small particles that are too small to see, but that make up other kinds of particles, like protons and neutrons. QCD helps us understand how quarks join together to form these bigger particles, and how these bigger particles interact with other particles. QCD helps us understand why some particles are bigger than others and how these particles behave.