Investigates whether pupils aged 12-15 years perceive physical quantities as intensive or extensive. Written questionnaires were administered to 300 pupils comprising four tasks for each intensive quantity, density and pressure. Analysis reveals three models of consistent pupils' reasoning. (Author/SOE)

Reviews two videotapes on motion: (1) "Demonstrations of Physics, Volume 1, Motion" and (2) "Center of Mass Motion." Describes the content, strengths, and weaknesses of each video. (YP)

Demonstrates what theoretical physicists make a rule using juggling. Provides the thinking process and calculating procedure. (YP)

Describes the scientific work of several women, including Marie Curie, Lise Meitner, Ida Noddack, Irene Curie, Marguerite Perey, Chien-Shiung Wu, and Maria Mayer. Discusses the connections between their discoveries. Thirty-six references are listed. (YP)

Discusses a demonstration of vertical collision of two balls. Shows the theoretical height ratio using mathematical expression and diagrams. Compares it with researchers' experimental results. Expands the two-ball collision to multi-ball system. (YP)

Describes a demonstration on the stability of a ladder. Provides the demonstration method, diagram showing forces acting on a ladder, and three demonstration pictures. (YP)

Asks the relationship between mass and skidding distance. Provides a problem with illustrations and an answer. (YP)

Presents the LOGO computer language as a source to experience and investigate scientific laws. Discusses aspects and uses of LOGO. Lists two LOGO programs, one to simulate a gravitational field and the other projectile motion. (MVL)

Presents three motion experiments that use magnetic switches for marking position and time involving an inclined plane, an air track, and sprinting. (JRH)

Presents a simple experiment--a marble rolling on a tilted desk--to introduce students to moving bodies. Makes difficult subjects such as measurement, calculus, modeling, and uncertainty easier to identify by putting them into a simple context. Discusses misconceptions, models, and measurements. (JRH)

Presents a demonstration used to give meaning to the terms node, amplitude, wavelength, and quantization. (JRH)

Describes a method for making a Wilberforce pendulum in which a mass at the end of a spring can vibrate up and down and also rotate about an axis collinear with the spring. Cost of production is around $15. (MVL)

Presents activities to teach students the science concept known variably as center of gravity, center of mass, center of balance, or balance point. Gives examples of activities for the exploration phase of study, concept introduction phase, and concept application phase. (TJQ)

Describes a traveling-wave demonstration that uses inexpensive materials (crepe-paper streamers) and is simple to assemble and perform. Explains how the properties of light waves are illustrated using the demonstration apparatus. (LZ)

Describes a technique for extracting a radioactive source from the atmosphere using a balloon, as a strategy to generate students' enthusiasm for and understanding of radioactivity experiments. (JRH)