Quantum

The smallest amount (or unit) of any kind of thing. For example, the smallest amount of electricity would be a single electron. The science of small particles is called "quantum mechanics."

Quarks

Quarks and leptons are the smallest things that are known to exist and are called fundamental particles. There are six types or flavors of quarks: up, down, charm, strange, top, and bottom. These are what protons, neutrons and many other particles are made of. Quarks can interact by the strong force since they have the property of color. The other group of particles is the leptons. click to enlarge.