ISEN-ASTC-L is a service of the Association of Science-Technology Centers Incorporated, a worldwide network of science museums and related institutions. ***************************************************************************** I also need to add my 2-cents about safety. Unfortunately too many people don't remember the 'don't do this at home aspect'. And even though few people have access to liquid nitrogen, many have access to dry ice . . . and why not try it out with that? Check out this link for an example: http://www.west.net/~science/co2.htm Denise *********************************************************************** More information about the Informal Science Education Network and the Association of Science-Technology Centers may be found at http://www.astc.org. To remove your e-mail address from the ISEN-ASTC-L list, send the message SIGNOFF ISEN-ASTC-L in the BODY of a message to [log in to unmask]