Mousetrap Chain Reaction, 7D20.10




A large acrylic enclosure (60"x32"x40") contains 251 mouse traps in a 15x17 array are set with 251 ping pong balls in top. Then triggered with 1 to 3 ping pong balls from above.



ID Number

Mousetrap Chain Reaction

MP, Large Equipment Area


Important Setup Notes:

  1. This demonstration requires a minimum 24 hour notice.

  2. This demonstration requires a minimum 45 minutes to set up.

  3. Back-to-Back lectures is NOT possible; We'll do one lecture one day and the other the next day.


  1. Photos below show the setup in stages. First Clear off the ping pong balls, straiten the traps and tails. This is the storage position.
  2. Set all traps; only this part can be a two person job. Start from the back left or right corner work toward the center then front.
  3. Let system of set traps seat for several minutes (5-10) to let the week one snap. If any snap, reset them. Periodically bang and kick that cage to set off any weakly set traps and then reset them. Do this several time until it is hard to snap more then one.
  4. Ping pong balls "must be" placed on the traps within the classroom. Thus, move the cage to were the demonstration is to take place. When in place, shake and kick that cage to set off any weak traps and then reset them.
  5. With a steady hand, start placing the ping pong balls on each and every trap as shown in the below photos. Start from the back right corner and work toward the center. The ping pong balls will like to be placed in pairs and on a diagonal. See photos below.
  6. Make sure there is two to three ping pong balls in the drop tube trigger on top of the cage. See photos below.
  7. CAREFULLY place the back panel on it's holders on the cage. This is the number on point were the system can go off.
  8. After used, put the cage back in it's storage position by clear off the ping pong balls, straighten the traps and tails.

Cautions, Warnings, or Safety Concerns:

  1. System can spontaneously go off at any time during setup.

  2. Mouse traps can hurt, if the get your finger.
  3. This demonstration as about a 2% failure rate. Other words, about 2 out of 10 setup is a miss fire.


Two to three ping pong balls are dropped from a pull string trigger that is located on top of the cage. This starts a cascading chain reaction with the traps, sending there ping pong balls into the air to set off another trap and so on. When all done about 90% of the traps have gone off and it only takes about 3 seconds.











7D2010MousetrapReactor-01.mp4 .... From Prof. Carlsmith's Phys:205 Course

Slow Motion Video


  1. Department of Astronomy & Physics, Saint Mary's University, Halifax, N.S., Canada

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fw: MousetrapChainReaction (last edited 2013-08-06 19:36:44 by srnarf)