A thermal oscillator is a self-sustained, nonlinear oscillating system. One part of the system vibrates continuously because of the transfer of heat. Four such devices, two new and two demonstrated in the 19th century are described. Although each depends on the periodic redistribution of heat, they are all quite different. (Author/JN)

Describes an experiment to give students exposure to digital control widely used in industry but not given much attention in most undergraduate process control curricula. Students write their own control programs and experimentally determine the transfer functions for all system components. Also describes experimental apparatus used in the…

Discusses analytical design and experimental verification of a PID control value for a temperature controlled liquid delivery system, demonstrating that the analytical design techniques can be experimentally verified by using digital controls as a tool. Digital control instrumentation and implementation are also demonstrated and documented for…

Background information, procedures, and results of an experiment suitable for measuring subpart per million concentrations of anionic surfactants in natural waters and waste effluents are provided. The experiment required only a spectrophotometer or filter photometer and has been successfully performed by students in an undergraduate environmental…

Tandem electrostatic accelerators produce beams of positive ions which are used to penetrate atomic nuclei in a target, inducing nuclear reactions whose study elucidates varied properties of the nucleus. Uses of the system, which acts like a mass spectrometer, are discussed. These include radiocarbon dating measurements. (JN)

Several activities related to color are discussed. These include placing different colors on a disk which, while spinning, appears to be white. Also discusses complementary and primary colors. (JN)

A lesson for a sixth grade class that came out of an article in a Sunday newspaper is described. The instruction centered around an experiment in probability that was seen to provide an opportunity to add to pupil intuitive understanding of some basic notions. The lesson was viewed as worthwhile. (Author/MP)

Describes contruction of an instrument which measures effects of reversible physiological changes on the motor coordination of laboratory animals. The "rotarod" is used to perform carefully planned, humane experiments which produce quantifiable results. A photograph and diagram of the apparatus are provided. (JN)

Suggests using African-clawed frogs (Xenopus laevis) for conditioning (behavior) experiments. Other experiments using these easy-to-care-for frogs are outlined. (JN)

Three physics experiments are described, minimizing difficulties for amateur experimenters. One experiment demonstrates the Doppler shift of light, converting the phenomenon into sound. The second measures Planck's constant. The third measures the universal gravitational constant, which does the same in Newton's theory of gravitation. (Author/JN)

Describes three experiments (also useful as demonstrations) using a "thorium cow," a device which concentrates the daughter products from thorium compounds by precipitation on a charged electrode. (JN)

A chromatographic procedure for analyzing organophosphorus pesticides (such as PCB's, nitrosamines, and phthalate esters) in orange juice is described, including a summary of the method, instrumentation, methodology, results/discussion, and calculations. (JN)

Provides information on collecting and maintaining termites and for using these insects in behavioral studies (trail following, recognition, food choice, reproductive behavior, and behavior in a magnetic field) and termite control experiments (preventive construction techniques, termite repellents, using soil or wood pretreatment, and the bait…

Compares the 1929-32 Venereal Disease Control Demonstration Project conducted among Southern Blacks with the 1932 Tuskegee Syphilis Experiment. Asserts that while the latter involved unethical research activities, the former fell outside the realm of research ethics, because it exploited human subjects for political gain. (Author/MJL)

Describes a low-cost instrument using a solar cell as a sensor to measure both instantaneous and integrated value of solar flux. Constructing and calibrating such an instrument constitutes an undergraduate experimental project, affording students an opportunity to examine a variety of aspects associated with solar energy measurements. (Author/SK)