Presents a letter that illustrates the problems and issues that arise when educators reproduce copyright material for classroom dissemination. Indicates the present state of legal confusion that exists in this area. (GS)

Relates the story of Wilhelm Conrad Rontgen and presents one view of the extent to which the discovery of the x-ray was an accident. Reconstructs the sequence of events that led to the discovery and includes photographs of the lab where he worked and replicas of apparatus used. (GS)

Reports on the status of physics teaching in Montana in 1972-73, compares the results to 1958 and 1959 status studies to determine the effect of past attempts at change, and makes comparisons to recent findings in Wisconsin and New England. (Author/GS)

Explains the asymmetry between left-right and up-down when your image is viewed in a plane mirror in psychological rather than physical terms. (GS)

Relates the advantages of using child-child and adult-adult transactions in the physics classroom and laboratory including implications for laboratory instructional strategy. (GS)

Describes an out-of-doors, partially unstructured experiment to determine the coefficient of friction for a moving car. Presents the equation which relates the coefficient of friction to initial velocity, distance, and time and gives sample computed values as a function of initial speed and tire pressure. (GS)

Presents one approach to solving problems concerned with minimum stopping distances. In this approach differing negative accelerations are considered in addition to the speed and reaction time. (GS)

Gives information for producing 35mm slides and for constructing a copy stand for the production of close-up photographs. (GS)

Describes the process of high gradient magnetic separation which gives promise as a method of large scale removal of colloidal impurities including bacteria and viruses. Examples and diagrams are included. (GH)