Discusses the use of 40 kHz ultrasonic transducers to study wave phenomena. Determines that the resulting wavelength of 9 mm allows acoustic experiments to be performed on a tabletop. Includes transducer characteristics and activities on speed of sound, reflection, double- and single-slit diffraction, standing waves, acoustical zone plate, and…

Describes the use of geiger counters for scientific investigations and experiments. Presents information about background radiation, its sources and detection. Describes how geiger counters work and other methods of radiation detection. Provides purchasing information for geiger counters, related computer software and equipment. (MCO)

Discusses ways to simulate a probability problem of interest to middle school students in which students calculate the average number of packets of trading cards purchased to obtain a complete set of cards. Simulations utilize a spinner, a table of random numbers, and a computer. Includes the BASIC program utilized in the simulation. (MDH)

Authors discuss "the scientific method" and assert that laboratory scientists ask questions but seldom state formal hypotheses to be answered by controlled experiments. Authors suggest that experimental results should not be viewed as fact, and students should not be required to memorize the steps of the scientific method. (PR)

Presents an experiment based on the principles of rectilinear motion of light operating in a pinhole camera that projects the image of an illuminated object through a small hole in a sheet to an image screen. (MDH)

Presents two demonstrations to compare the differences between the screen reproductions of a bulb when using a converging lens and a pinhole and how that reproduction image reaches the observer's eye from multiple vantage points. (MDH)

Reviews diverse types of computer programing languages and provides examples of representative programs from the most significant languages in use. Matches programing languages most suitable for various types of experimental applications for the amateur scientist. (JJK)

The following administrative aspects of scientific experimentation with human subjects are discussed: the definition of human experimentation; the distinction between experimentation and treatment; investigator responsibility; documentation; the elements and principles of informed consent; and the administrator's role in establishing and…

Describes a theoretical development to explain the shadow patterns of an object exposed to an extended light source while held at varying distances from a screen. The theoretical model is found to be accurate in comparison with experimental results. (MDH)

Describes an experiment used to demonstrate basic physics concepts regarding acoustic waves used by oceanographers to obtain seabed profiles. (ZWH)

Equipped with a plastic film can and a pin, students can gain a better understanding of chromatic aberrations and inner eye phenomena, light, lenses, pinholes, shadows, and ray diagrams. (ZWH)

Uses Dictyostelium discoideum to aid in introducing cell differentiation to students. Students engage in a laboratory exercise that allows them to investigate the means by which embryonic cells choose developmental pathways. (ZWH)

Describes an experiment designed to help students gain a better understanding of the characteristics of various electronic components by incorporating a dual-trace oscilloscope in the X-Y mode in addition to direct observations of phase shifts of various signals into a laboratory exercise. (ZWH)

Presents an inexpensive take-home laboratory activity designed to enhance students understanding of atmospheric pressure by allowing them to engage in a hands-on, discovery approach to physics. (ZWH)

A procedure for purifying DNA using either bacteria or rat liver is presented. Directions for doing a qualitative DNA assay using diphenylamine and a quantitative DNA assay using spectroscopy are included. (KR)