The "word problem" is stated for a given collection. Facts regarding Dehn's Algorithm, definition of Thue systems, a rewriting system, lemmas and corollaries are provided. The situation is examined where the monoid presented by a finite Thue system is a group. (DC)

Introduces "The Bouncing Ball Project" made for teaching mathematics through practical mechanics. Describes four activities in the project: what is bounciness; drop height and rebound height; timing the bounces; and extension activities. Provides many worksheets, graphs, and a list of five other projects. (YP)