Discusses the energy flux-density of two beams of light of equal energy that are intersected at a given angle. Examines an apparent contradiction to the physics law of conservation of energy known as Vavilov's paradox. (MDH)

Provides diagrams and text to describe the procedures and results of an experiment used to introduce students to parametric resonance. (ZWH)

Describes an experiment that demonstrates the use of Kirchoff's rules in the analysis of electrical circuits. The experiment also involves the solution of a linear nonhomogeneous differential equation that is slightly different from the standard one for the simple RC circuit. (ZWH)

Describes the use of a microcomputer as an intervalometer for the control and timing of several flash units to photograph high-speed events. Applies this technology to study the oscillations of a stretched rubber band, the deceleration of high-speed projectiles in water, the splashes of milk drops, and the bursts of popcorn kernels. (MDH)

Describes science demonstrations with light-emitting diodes that include electrical concepts of resistance, direct and alternating current, sine wave versus square wave, series and parallel circuits, and Faraday's Law; optics concepts of real and virtual images, photoresistance, and optical communication; and modern physics concepts of spectral…

Recounts an anecdote about a teacher's science anxiety resulting from the mysterious results of a plant growth experiment. Students found that bean plants grew taller in a dark closet because of etiolation. Points out that teachers need to deal with experimental results objectively and resist looking for "right" answers. (MDH)

Discusses difficulties of learning and teaching science at the secondary school level. Highlights include the nature of science concepts; multilevel thought; the use of scientific experiments; language problems; students' learning processes; and an information processing model that can be used to guide thinking and research in this area. (10…

Discusses how to build an inexpensive Young's modulus apparatus and also a lens with an adjustable focal length. Describes the demonstration of moving a peeled, hard-boiled egg in and out of a flask whose neck is slightly smaller than the egg. (MVL)

Describes an experiment where students test the furcula or wishbone of a bird for its springlike properties. (PR)

Presents the general theory to explain chemical movement in soil. Describes classroom demonstrations with visually stimulating results that show the effects of soil structure, soil texture, soil pH, and soluble organic matter on that movement. (MDH)

Science fair mentorship programs let students investigate a wide variety of science topics under the guidance of interested community members. These programs enhance the relationships among school, community, and home. (PR)

Describes an investigation in which students predict and verify the effect that the number of clicks of a toy copter gun has on the height that the copter will attain. Provides follow-up questions for the students. (MDH)

Describes the biochemical structure and functions of the enzyme chymosin. Presents activities to familiarize students with fundamental aspects of enzyme-substrate interaction. (WRM)

Presents a procedure for creating a colored superabsorbant polymer gel. Pieces of the gel can be used to demonstrate convection currents in heating water. (WRM)

Describes the Environmental Buddies program designed to pair fourth-grade (mentors) and kindergarten (proteges) children to work on science investigations centered around ecological themes. Details program components, including the following: investigations that interest and challenge both ages, careful student pairing, emphasis on mutual benefits…