Weak nuclear force: acts on all matter, nuclear range, weak

Three profiles are done: gravity, the electromagnetic force, the strong force. The last of the four is the one you will never feel. It holds nothing up, lifts nothing, and binds nothing you can see. Yet it belongs on the list.

This lesson gives the fourth profile, the weak nuclear force: what it acts on, how far it reaches, and how strong it is.

You've already seen the neutrino: a lepton with no electric charge and almost no mass. Keep it in mind. It is the particle that makes this force easiest to see on a profile card.

The first line says what the force acts on: the weak nuclear force acts on all matter particles, quarks and leptons alike. That reach is wider than the strong force's. The strong force skips the leptons; the weak force touches every matter particle there is.

The second line gives the range: the weak nuclear force acts only over distances about the size of an atomic nucleus or smaller.

The third line gives the strength: the weak nuclear force is weaker than both the strong force and the electromagnetic force.

Physicists shorten this name too: the weak nuclear force is called the weak force for short.

Now the neutrino earns its place. It has no charge, so the electromagnetic force skips it. It is a lepton, not made of quarks, so the strong force skips it. The weak force is the only force besides gravity that a neutrino feels.

Your turn