These problems have been used in introductory and advanced science classes of all sizes. The authors have included information on the setting in which the problem has been "field tested"; please contact them at the e-mail addresses provided with any questions you might have. We invite you to use these in your classroom; we only ask that you credit the source, and ask colleagues to do the same if you pass them on.
Two additional problems (biology, physics) can be found in an article in About Teaching (Spring, 1996) entitled "Problems: A Key Factor in PBL." Reprints of the article can be obtained from the Center for Teaching Effectiveness, University of Delaware, Newark, DE 19711.