An experiment intended to familiarize a student with the musical scale and the technique of tuning an instrument by listening for beats is described. From the dial reading of the oscillator frequency and the counted beats frequency, the student then computes the frequency of each musical note over one full octave. (Author)

The author presents a dichotomous key to 29 tree cones, fruits, and nuts of eastern United States. Students can use the key to identify at least 10 species in a 1-hour laboratory assignment. This key uses reproductive structures that are significantly different from others. These structures are durable enough to be used in the laboratory for many…

Presents an activity that provides students an opportunity to explore the tempo and mode of evolution by analyzing data and constructing two evolutionary trees, one gradualistic and one punctuated. (ZWH)

Describes a convincing and practical hands-on way to illustrate to students one part per million. (ZWH)

Notes that rodents and rabbits share many characteristics that make them suitable classroom pets and gives background information on rabbits, guinea pigs, hamsters, and gerbils. Offers advice on buying a classroom pet, the pet's home, feeding, helping the children handle the pet, and pet health and family planning. (TJQ)

Describes a classroom use of the Hertzsprung-Russell diagram to infer not only the properties of a star but also the star's probable stage in evolution, life span, and age of the cluster in which it is located. (ZWH)

Activities in which students build their own simulations of fossils, using seashells, chicken bones, toy dinosaurs, or leaves as models and plaster of paris, sand, mud, clay, or a mixture of gravel and clay as a matrix are presented. Curriculum extensions are included. (KR)

Presented are seven investigations that examine circadian rhythms. Topics include attention span, body temperature, rhythms found in rodents and spiders, and possible genetic determination of circadian rhythms. Background information on plants and animals is given. (KR)

A low-cost procedure for metallizing a silicon p-n junction diode by electroless nickel plating is reported. The procedure demonstrates that expensive salts can be excluded without affecting the results. The experimental procedure, measurement, results, and discussion are included. (Author/KR)

Perturbation theory is presented as an invaluable tool for solving a majority of physically interesting problems involving both macroscopic and microscopic objects. Its use in Newtonian mechanics is emphasized.. The method is illustrated with three examples. (KR)

This activity makes a barometer out of 50 feet of clear vinyl tubing and a gallon of tea. The barometer is used in a building stairwell where students have easy access to the tube. Discusses possible pitfalls, vapor pressure, elevation, and weather influences. (MVL)

Describes a real life example of natural selection that can be used instead of computer simulation to teach evolution to students. (ZWH)

Describes an enjoyable and fascinating experience that involves the cultivation of oyster mushrooms. By allowing students to participate in this process, the students are able to better understand the biology and utility of fungi. (ZWH)

Describes procedures for designing your own huge scale model of the solar system. (ZWH)

Discusses the procedures used by students to design an interactive astronomy display case. (ZWH)