Willard Libby’s clock, as a working exhibit. Living tissue is in equilibrium with atmospheric ¹⁴C; after death the isotope decays with a half-life of 5,730 years (Cambridge). Enter remaining fraction or a conventional age. This is the uncalibrated BP clock — not IntCal, and not a lab report.
Half-life: Godwin 1962 / Cambridge 5,730 ± 40 a; Libby’s original 5,568 a is still used to define “conventional radiocarbon years BP” (before 1950). Atmospheric ¹⁴C is not constant (Suess effect, bombs, solar cycles) — a real date needs an IntCal calibration curve. The hall does not pretend otherwise. Useful to ~50,000 years; beyond that the remaining activity is a whisper.