Presents the theoretical explanation of the observation that when a pen that is stuck in a hard rubber ball and dropped, the pen may bounce to several times the dropped height. Includes the procedure and models created to explain the observations. (DS)

Traces the history of the search for the ultimate nature of matter. The work of outstanding physicists since the late nineteenth century is discussed as it relates to the total picture of the search for a single unifying theory. (SA)

Presents an examination of the buoyancy principle which can serve as a simple but rigorous illustration of a falsification test that not only clears up a possible misconception but also points the way to a number of practical uses of buoyancy measurements that have not generally been recognized. (MVL)

Presents a unit of three lessons to teach Newton's Laws of Motion. After rotating through learning centers, answering questions, and recording observations, students are asked to generate a "class law" that explains the scientific phenomenon they observed. (MDH)