Describes an experiment that illustrates the use of the preparative ultracentrifuge in isolating and purifying bacterial ribosomes, determines the sedimentation coefficients of the ribonucleoprotein particles, and demonstrates the subunit structure of the 70-S ribosome and the role of the magnesium ion in the association of subunits. (Author/GS)

Describes a laboratory experiment designed to merge the concepts and techniques of the analytical-organic-physical subdivisions and introduce the student to a decision-making situation. Presents a discussion of the use of the experiment in attaining these goals and provides typical data obtained by students. (GS)

Reports a modification of a simple method previously described for determining enthalpies of sublimation and comments on some of the method's inherent limitations. (Author/GS)

Describes an experiment designed for second-level summer school chemistry students enrolled in Great Britain's Open University. (GS)

Suggests current scientific literature published in journals of biological research as a source of new, interesting, and enlightened experiments to reinforce an understanding of the process and sense of science. Presents an exercise developed using current literature. (EB)

Describes the use of films as primary learning material, aimed at developing some of the higher level skills which are the, often unreached, objectives of practical courses. Results of a first trial use are cited. (EB)

Presents comments on problems voiced by teachers about conducting science fairs with middle school children, also cites some advantages of science fairs. A list of simple experiments is offered that are considered within the interests and intellectual range of middle school children. (Author/EB)

Presents part of a new series aimed at providing exploratory activities for preschool children as they seek to become acquainted with the world in which they live. (Author/EB)

Describes a model system to illustrate many of the biochemical and chromosomal processes involved in the transmission of genetic material. Uses commercially available beads. (BR)

Describes two exercises which use data of sporting events (running) in conjunction with biological factors as exercises in interpreting data. (BR)

Describes construction and use of a simple auxanometer which students can use to accurately measure root growth rates of intact seedlings. Typical time course data are presented for the effect of ethylene and indole acetic acid on pea root growth. (Author/BR)