Disclaimer:

Reprinted by permission of Dick Berg, University of Maryland, for use on this website.

The demonstrations contained and referenced herein are listed for the purposes of cataloging and describing physics demonstrations which should be conducted only under the direction of a trained instructional support professional or physicist. These demonstrations are not presented for the purpose of being conducted by persons unconnected to this Facility and/or persons not consulting with or being supervised by the recognized instructional support professional or physicist and his/her staff. The University is responsible only for those demonstrations carried out using its own equipment using established safety and scheduling policies, and bears no responsibility for those choosing to use this source material for their own purposes. All demonstrations described and contained herein are public domain, and can also be found in reference materials in libraries, bookstores, and electronic sources.

Further information regarding legal liability in use of demonstrations and labs will be found on the web site Injuries in School/College Laboratories in USA.

The University of Iowa Disclaimers:  U of Iowa Disclaimer All Rights Reserved.

The trick with the coin puzzle is to get the coin out of the holder.  Tilting the puzzle back and forth will not move enough of the ball bearings out of the way to release the coin.  Spinning the puzzle will move the ball bearings outward releasing the coin.