Described is an alternative method of culture isolation that uses streaking on specialized media. An activity in which different media are tested for selectivity is presented including a list of materials and procedures. A chart of colony morphology is given. (CW)

Describes three activities: "Solar Approach to Ohm's Law," dealing with the Ohm's law and the inverse square law; "Using LED's to Demonstrate Induced Current," showing Faraday's law and Lenz's law by using light emitting diodes (LEDs); and "The Helium-Filled Organ Pipe," discussing a discrepancy between theory and experiment. (YP)

Explains strategies for motivating and getting student's attention in science. Presents a laboratory procedure for generating hydrogen using an Erlenmeyer flask and a one-holed stopper apparatus to fill a balloon which is used to produce a dramatic explosion. Safety precautions are cited. (RT)

Describes a demonstration which allows students to witness a type of continuous spectrum and an absorption spectrum. Provides a diagram and explanation for the construction of an absorption box. (RT)

Describes a thin film rectangular dielectric waveguide and its laboratory use. Discusses the theory of uniaxial thin film waveguides with mathematical expressions and the laboratory procedures for a classroom experiment with diagrams. (Author/YP)

Presents an experiment to measure the threshold limit of the adhesion of water. Discusses types of thresholds and pseudo thresholds. Provides 13 examples of thresholds in science. (MVL)

Described is a science activity for intermediate grades which uses science skills to solve a mystery. Fingerprints, footprints, chromatography, invisible ink, and microscopic analysis are used in the activity. Observation, data analysis, and deductive reasoning are stressed. (CW)

Provided are six ideas for lessons and projects which could be done in secondary school science classes. Topics include alcohol; the relationship between water availability and water loss in plant growth; the effects of acids on teeth; woodlice clustering; the ecology of frogs; and human blood pressure and heart rate. (CW)

Described is a technique for monitoring the quality of freshwater aquatic habitats. Methods, comparison of samples, equipment, and data analysis are discussed and an example is presented. (CW)

Described are the techniques and results of using this tissue culture activity. Discusses the advantages of using such techniques in teaching alternation of generation life cycles to biology students. (CW)

Studies the polarization effect on water by cations and anions. Describes an experiment to illustrate the polarization effect of sodium, lithium, calcium, and strontium ions on the water molecule in the hydration spheres of the ions. Analysis is performed by proton NMR. (MVL)

Presents three models that have been effective for teaching chemical equilibrium and Le Chatelier's principle: (1) the liquid transfer model, (2) the fish model, and (3) the teeter-totter model. Explains each model and its relation to Le Chatelier's principle. (MVL)

Develops a lab experiment for introductory instrumental analysis that requires interference studies and optimizing of conditions. Notes the analysis of the aspirin is by visible spectrophotometric assay. Gives experimental details and discussion. (MVL)

Describes a laboratory experiment designed to encourage laboratory cooperation among individual undergraduate students or groups. Notes each student contributes results individually and the exchange of data is essential to obtain final results. Uses the polarographic method for determining complex metal ions. (MVL)

Describes a laboratory experiment that measures the amount of ascorbic acid destroyed by food preparation methods (boiling and steaming). Points out that aqueous extracts of cooked green pepper samples can be analyzed for ascorbic acid by a relatively simple redox titration. Lists experimental procedure for four methods of preparation. (MVL)