Deals with the conversion of electronic hand calculators to timing devices. This article illustrates a conversion of a rather versatile calculator by means of simple and inexpensive circuitry. (HM)

The chemical system of rubbery elasticity is presented. Several references are given from which to extract experiments and problems for students. (SA)

Detailed descriptions are given of two procedures for measuring the radius of the earth, one using a rule and the other a stopwatch. (MP)

Discusses new experiments that are being designed to solve the solar neutrino problem and determine the power source of the sun. (HM)

Lists materials and methods for an experiment that demonstrates the concept of glomerular filtration rate (GFR) using anesthesized dogs. In the dog, GFR is equivalent to the renal plasma clearance of exogenous creatinine. (CS)

Describes an experiment using rats that demonstrates contractile characteristics of normal and hypertrophied muscle. Compensatory hypertrophy of the plantaris muscle is induced by surgical removal of the synergistic gastrocnemium muscle. Includes methods for determination of contractile properties of normal and hypertrophied muscle and…

Scientific method marks the learning in a student flight center. (Editor)

Describes an experiment in which chemistry students determine the efficiency of a laboratory burner used to heat water. The reaction is assumed to be the complete combustion of methane, CH4. The experiment is appropriate for secondary school chemistry students familiar with heats of reaction and simple calorimetry. Contains pre-laboratory and…

Explains the allium test in which roots are excised from onion bulblets grown in aqueous solutions of a test agent. Root tips are then isolated and stained with aceto-orcein, and chromosomal aberrations are microscopically observed. (Author/AIM)

Thermochromism is the reversible change of color of a solid when heated or cooled. Describes the preparation of thermochromic compounds that exhibit sharp thermochromic transitions. (DKM)

Presents a simple method of recording root growth which can be used in schools. A slant board system was designed to facilitate access to roots to enable measurements to be made, essentially forcing the roots to grow in a two-dimensional form which allows each student to observe and record root growth over several weeks. (AIM)

Describes an approach to teaching physics to science teachers using the history of science. Reports that history becomes more useful to teachers when explicitly combined with investigative experimentation, which in turn can benefit from various uses of the history of science. Contains 18 references. (JRH)

Describes an approach to teaching atomic, nuclear, and particle physics using the history of the most important discoveries in that field. Uses the manuscripts, first publications, measurements and data of initial discoveries, and the photos of apparatus and of famous physicists to arouse student interest. Presents examples from the life and work…

Describes a technique that measures the deformation produced in a plastic material by a falling ball in order to compute the ball's kinetic energy. Varying the parameters produces accurate results and gives students a good understanding of the measurement of energy. Combines various mechanical concepts that students have learned separately in…

Presents a laboratory model system for introductory microbiology students that involves hands-on studies of bacteria vectored in soil nematodes. Describes a series of experiments designed to demonstrate vector-fomite transmission, bacterial survival, and disinfectant activity. Introduces the concept of genetically engineered microorganisms and the…