Defined model

A drop in an Olympic pool

Probability:
6.67 × 10⁻⁹%
Odds:
1 to (1.5 × 10¹⁰)
dBan
−101.8 dBan

Mark one drop-sized portion of this competition pool, then choose uniformly from its water. Finding that exact portion is a one-in-15-billion event.

Calculation

V = 50 × 25 × 3 × 1,000 = 3,750,000 L; drop volume = 0.25 mL = 0.00025 L; p = 0.00025 / 3,750,000 = 1 / 15,000,000,000

Assumptions

The rectangular volume model uses the London Aquatics Centre competition pool’s published 50 × 25 × 3 m dimensions. The adopted 0.25 mL faucet-drop estimate comes from USGS. The water volume is partitioned conceptually into equal drop-sized portions, and one is selected uniformly. One portion is designated in advance.

Sources

  1. Queen Elizabeth Olympic Park: London Aquatics Centre London 2012 competition pool: 50 m long, 25 m wide and 3 m deep
  2. USGS Water Science School: how much water does a dripping faucet waste? 2019 faucet-drop estimate: 0.25 mL per drop, within a stated 0.2–0.333 mL range