What is the origin of the phrase flash in the pan?

Answer 1

This phrase stems from the 'flintlock' small arms (hand-held weapons) of the 17th to 19th centuries. The ignition mechanism of these weapons involved a small quantity of gunpowder in a small dish (the 'pan') being ignited by sparks struck from a metal plate by a flint. This gunpowder would then send a flame through a small hole into the main charge that had been loaded into the barrel.

Occasionally the main charge would not ignite following the burning of the gunpowder in the pan. Hence the phrase 'a flash in the pan' refers to short-lived activity that fails to lead to more substantial or sustained action.

Answer 2

Before bullets were manufactured in their own metal jackets containing the powder charge necessary to propel them, it took two ignitions of gun powder to shoot a fire arm. You pull the trigger on a flintlock rifle, causing a piece of flint to hit a striker, sending a spark into a small amount of gunpowder in the PAN, which contains a small passage to the barrel. When the powder in the pan ignites with a flash, it sets off the charge in the barrel, which shoots the bullet. If the powder in the pan fails to ignite the charge in the barrel, you have "a flash in the pan." Now mostly used metaphorically to mean a success that does not lead to further successes, a one-hit wonder.