To simulate chain reactions we use 22 mouse traps glued to a round piece of thick veneer, each loaded with 1-2 ping-pong balls. The array of mousetraps is covered with a clear plexiglass dome (pic. 3). A short cord is attached to one of the traps. A “chain reaction” is triggered when the instructor pulls this cord and discharges the first trap (pic. 4). Within a second, fast flying ping-pong balls fill the space inside the dome and all traps are discharged (pic. 5). This demo is well received by the audience.

Note: Preparation for this demo can be very painful for instructor’s fingers, so please follow the procedure.

Procedure

1. While charging the mouse traps, insert wooden wedges to prevent them from going off (see pic. 1 and 2)
2. When all traps are charged and ping-pong balls are placed, carefully remove the wedges starting from the center. The very last wedge should be removed from the mousetrap with the cord attached.
3. Carefully lower the plastic dome over the setup.
4. Pull the cord slightly to set off the “chain reaction.”