A scientific wager is a wager whose outcome is settled by experiment or observation, following the scientific method. It typically comprises a commitment to pay out when a currently-unknown or uncertain statement is resolved, and either proven or disproved. Some wagers have specific date restrictions for collection, but many are open. Wagers occasionally exert a powerful galvanizing effect on society and the scientific community.
Notable scientists who have made scientific wagers include Stephen Hawking and Richard Feynman. The Stanford Linear Accelerator has an open book containing about 35 wagers in particle physics dating back to 1980; many are still unresolved.