Mousetrap Chain Reaction

Flying corks can travel with significant velocity and pose an eye hazard. The demonstrator must wear safety glasses. Ensure adequate separation between the trap array and student seating. Consider using a transparent barrier or performing the demo in a demonstration pit.

Not all traps will trigger during the chain reaction (typically 80-90% success rate). Remaining set traps are hazardous during cleanup. After the reaction completes, use a long wooden block or dowel to safely trigger all remaining traps from a distance before approaching the array. Never reach into the array with hands immediately after the demonstration.

Purpose

Models runaway nuclear fission using mousetraps as uranium atoms and corks as neutrons. Dropping a single cork into the array triggers an exponential chain reaction, illustrating critical mass and neutron multiplication.

Two display cases showing wooden mousetraps with cork cylinders: top case shows orderly array of approximately 100 set traps, bottom case shows chaotic aftermath with triggered traps and scattered corks

Figure 1: Before and after states of the chain reaction demonstration. The organized array (top) represents subcritical arrangement of 'fissile material,' while the triggered state (bottom) shows the result of initiating the chain reaction, with approximately 85% of traps activated.

Warning: Eye Protection Required

Warning: Incomplete Reaction Hazard

Purpose

Safety Warnings

Warning: Eye Protection Required

Warning: Incomplete Reaction Hazard

Purpose