  We present quantitative measurements on a classic experiment proposed for the
first time in 1947 to illustrate the phenomenon of a chain reaction in nuclear
fission. The experiment involves a number of mousetraps loaded with solid
balls. Once one trap is made to snap, it releases two balls that cause other
traps to snap more traps and the result is a chain reaction. We report for the
first time that the mousetrap experiment can be fitted by a simple dynamic
model. We also discuss the significance of this experiment beyond nuclear chain
reactions, as providing insight in a variety of fields involving complex,
adaptive systems.
