Briefly discusses the theory of fatigue, and describes ways in which the fatigue rate in humans can be measured in the classroom using a simple physiological instrument, the ergometer. (JR)

Discusses the importance of developing elementary science textbooks which correlate highly with known readability levels of students, and reports the results of a study designed to compare readability levels and ranges of major elementary science texts with the approximate reading levels of each of the respective grades. (JR)

Describes how the continuous variation method may be used in senior chemistry classes at the secondary level. This technique allows for the detection of the one or more reactions that may occur in a system over a wide range of composition. (JR)

Discusses categories for science textbook analysis under the headings of: Readability, Content, Presentation of Material, Mathematical Demands, Appearance, Quality of Illustrations, and Teacher Aids. An analysis form is appended as a guide for science teachers and administrators in their evaluation and selection of appropriate science textbooks.…

Discusses the physical principles underlying the design of a small scale suspension bridge, including its types and strength calculations. Included are the working equation and two formulas for determining the load per unit length. (CC)

Reviews theoretical principles underlying the quark model. Indicates that the agreement with experimental results and the understanding of the quark-quark force are two hurdles for the model to survive in the future. (CC)

Discusses scientific information obtained from Pioneer 10's Jupiter flyby and the comet Kohoutek's first trip around the sun, including the high hydrogen emission of Jupiter's principal moon, Io. (CC)

Presents an outline of current knowledge relating to the response of radicles to a directional source of water (hydrotropism). New techniques are described that may be used in biology classes to demonstrate the hydrotropic response in plants. (JR)

Outlines the advantages of using the readily available eggs of the nematode Rhabditis in studying the early cleavage stages of animal development. Discusses the identification and life history of Rhabditis, how to culture and examine the organism, the cleavage stages and cell lineage, and sources of visual aids. (JR)

Discusses phenomena relating to the nature of soap films and describes soap film experiments suitable for secondary school science students. (JR)