Mousetrap Chain Reaction

Modern Physics > Nuclear Physics > Nuclear Reactions

DCS# 7D20.10

MOUSETRAP CHAIN REACTION

APPARATUS

50 mousetraps	202-04-C4
101 superballs	202-04-C4
wire mesh cage	atop 202-01

DESCRIPTION

This is a model of an uncontrolled nuclear chain reaction. The mousetraps represent uranium-235 (or other fissionable) nuclei and the balls represent neutrons. Initiate the reaction by dropping a ball into the cage. When it lands on a mousetrap, the mousetrap will launch two more balls and possibly the mousetrap itself, which will then trip other mousetraps, and so on, in a brief but dramatic cascade.

You can videotape the process with the digital camcorder and play it back at 1/5 speed. For slow motion playback, use the remote to press "play", then "slow".

NOTES

Position the ringstands at the corners of a 77 x 52 cm rectangle on a sturdy cart. Lower the cage over the ringstands and prop it up while setting the traps. The mousetraps fit inside the cage in a 4 x 11 or 4 x 12 array. Set the traps a row at a time, then load two balls per trap. Remove any particularly sensitive traps. When all traps are set and loaded, lower the cage. Slowly and carefully wheel the cart into the lecture hall.

Some balls and traps may fly out of the cage during the reaction.

Slow motion video (3 Mb)