In a study of play activities, 60 middle-class children ages 2.8-5.8 were tested on six object substitution tasks. Three dealt with puzzle games and three with pretence games. Results confirm Sliosberg's original contention that pre-school children discriminate between pretence and realistic games. (Editor/RK)

Shows how the Archimedes method is used to determine the density of a single crystal of ammonium oxalate monohydrate. Also shows how to calculate the density of other chemicals when they are available as single crystals. Experimental procedures and materials needed are included. (JN)

Reports a consecutive first-order reaction for which the concentrations of reactant, intermediate, and products can be determined simulataneously. This reaction is the epoxidation of 2,5-di-tert-butyl-1,4-benzoquinone (I) by alkaline hydroperoxidation using tert-butyl hydroperoxide and benzyltrimethylammonium hydroxide (Triton B) catalyst.…

Explains an experiment in which the rotation of a patch of skin on a tadpole results in a frog with rotated spots, proving that the spot pattern is determined long before it becomes visible. Procedures used are included. (DH)

Points out the benefits of "sciencing"--helping children learn the methodology and processes of scientific investigation through the use of play experimentation. (SKC)

Fifteen FORTRAN 77 programs are contained in the described package. Three programs are available for each of five forgetting models involving 5, 7, 8, 9, and 10-parameter models. The programs compute parameter estimates and test parameter estimates both between and within experimental conditions. (Author/GDC)

Described is the laboratory program for a second-year chemistry class at a Wisconsin high school. The laboratory stresses student-designed labs. Examples of topics considered are included. (RH)

Presented are the materials and a procedure for demonstrating the levitation of a magnet above a superconducting material. The demonstration can be projected with an overhead projector for a large group of students. Kits to simplify the demonstration can be purchased from the Institute for Chemical Education of the University of Wisconsin-Madison.…

Provides an overview on biological electron-transfer reactions, summarizing what is known about how distance, spatial organization, medium, and other factors affect electron transfer. Experimental approaches, including studies of bimolecular electron transfer reactions (electrostatic effects and precursor complexes), are considered. (JN)

This paper examines the major methodological advantages of random assignment for the purpose of estimating the effectiveness of current manpower policy. It also reviews the claimed methodological and ethical objections to experiments. The authors argue that the offsetting gain from experimentation is the inherent reliability of experimental…

Describes a physics experiment which demonstrates the pitfalls of assuming that a model which represents an ideal system is applicable to a real experiment. Explains how the failure may give greater understanding of the problem and may lead to improvements in the model. (ML)

Discusses an easy way of interfacing physics experiments to a microcomputer, providing information on the "analog input port" of a BBC microcomputer. Also describes a capacitor discharge experiment with suggestions for several student activities such as investigating decay curve shapes. Program listing is available from author. (DH)

Background information, procedures used, and results obtained are provided for an experiment in which a phase diagram is determined using a differential scanning calorimeter. Commercial samples of D-camphoric anhydride (Eastman Kodak) and D,L-camphoric anhydride (Aldrich) were used in the experiment. (JN)

Background information, procedures used, and typical results obtained are provided for an experiment in which students determine and compare the Arrhenius activation energies (Ea) for the hydrolysis of salicin. This reaction is subject to catalysis both by acid and by the enzyme emulsin (beta-d-glucoside glycohydrolase). (JN)

Discusses simple interval timers for microcomputers, including (1) the Jiffy clock; (2) CPU count timers; (3) screen count timers; (4) light pen timers; and (5) chip timers. Also examines some of the general characteristics of all types of timers. (JN)