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)

The theory of ecological competition, as used to explain community structure and specialization within species, also applies to the problem of coexistence among fast-food restaurants. This analogy is used in a simple laboratory exercise designed to teach competition theory and start students thinking about the urban environment from an ecological…

Describes classroom activities using algae, including demonstration of eutrophication, examination of mating strains, and activities with Euglena. Includes on algal morphology/physiology, types of algae, and field sources for collecting these organisms. (JN)

Presents an experiment which includes fractional distillation with gas-liquid chromatography (GLC) and infrared analysis. Objectives are to introduce students to fractional distillation and analysis of each fraction by GLC, to induce them to decide if each fraction is sufficient for infrared analysis, and to identify unknowns. (Author/JN)

Describes two simple physics experiments demonstrating the spin on baseballs or golfballs and the observed effects of falling coins when released together. (CS)

Describes materials and procedures for an experiment utilizing a live dog to demonstrate: (1) physiology of the salivary gland; (2) parasympathetic control of the salivary gland; (3) influence of varying salivary flow rates on sodium and potassium ions, osmolarity and pH; and (4) salivary secretion as an active process. (DS)