Weak Nuclear Force
Definition
The force behind radioactive decay — it can change one type of particle into another, powering the Sun's fusion chain.
Technical definition
One of the four fundamental interactions, mediated by W and Z bosons. It governs beta decay (neutron → proton + electron + antineutrino) and flavor-changing processes. Far weaker than the strong force at low energies; unified with electromagnetism at high energies (electroweak theory).
Example
Carbon-14 dating works because of the weak force — it slowly converts neutrons to protons, ticking at a 5,730-year half-life.
Common confusion
‘Weak’ refers to strength, not importance — the weak force drives the Sun's proton-proton chain and all beta decay. Without it, stars could not fuse hydrogen and the elements would not exist.