The Birthday of Charles‑Augustin de Coulomb (1736) — Inverse‑Square Forces

Charles‑Augustin de Coulomb, born 29 December 1736, discovered Coulomb’s law: the force between two electric charges is proportional to the product of the charges and inversely proportional to the square of the distance. The same inverse‑square relationship appears in Newton’s law of gravity. Coulomb measured these forces using a torsion balance — a sensitive device he also used to study friction. The unit of electric charge, the coulomb, is named after him. The mathematical form F = k q₁q₂/r² is one of the most important equations in electromagnetism.