The Journal of general physiology [J Gen Physiol] 1963 Nov; Vol. 47, pp. 241-64.
Chemical Phenomena, Chemistry, Electric Conductivity, Electricity, Equipment and Supplies, Hydrogen, Hydrogen-Ion Concentration, Light, Photic Stimulation, Photolysis, Retinal Pigments, Retinaldehyde, Rhodopsin, Rod Opsins, and Temperature
The change in electrical conductance of rhodopsin solutions was studied with flash-photolysis techniques. The whole pattern of the conductance change on illumination consists of three different processes: (I) the initial decrease, (II) the increase, and (III) the slow decrease, which are in decreasing order of reaction rate. The processes I, II, and III can be most distinctly recognized on flash illumination of acid, slightly acid, and alkaline rhodopsins, respectively. On the other hand, the bleaching of rhodopsin also shows at least three successive phases of different rates, but none of them corresponds in reaction rate to any of the processes of the conductance change. The conductance change may be related to conformational changes of opsin following photoisomerization of retinene, being due to hydrogen or hydroxyl ions and some other inorganic electrolytes. The amount of the change, especially the initial decrease, is proportional to the amount of rhodopsin bleached, even when the photochemical back reaction towards rhodopsin and isorhodopsin occurs in the chromophore depending on the intensity of illumination. Of the three processes, the slow decrease is most severely affected by aging, but the initial decrease and increase are slightly affected. These two processes promptly caused by illumination are connected closely to the conformational changes during the conversion of rhodopsin to metarhodopsin, and perhaps to the initial stage of excitation of rod cells.
This book contains 25 experiments designed to help students understand some of the science used every day. Each experiment includes a list of materials, a series of easy-to-follow steps, an explanation of the scientific principle demonstrated, and additional scientific facts and information. No special or expensive materials are required. Experiments are organized into five parts: light and optics, heat, earth science, chemistry, and electricity and magnetism. Experiments have imaginative names such as, "I Can See for Miles and Miles,""Steamed Fruit,""Grace under Pressure,""Hi-Ho Silver," and Dimmer Dementia." The book includes a glossary of terms and a reader reply form to suggest experiments created by students or teachers. (MKR)
This book was written on the premise that learning science should be fun and rewarding. The teacher may use it as the foundation for an extended middle school curriculum spanning more than one year or to supplement an existing curriculum with individual sections or exercises from the book. The activities have been organized and designed in a manner that allows the teacher tremendous flexibility. Each activity provides a clear purpose, step-by-step directions, leads easily to conclusions, and includes a teachers guide that has the following parts: goals, student objectives, prelab discussion, guide to the investigation, vocabulary, and additional resources. The guide contains seven sections: "Measuring Physical Quantities"; "Forces, Work and Energy"; "Heat"; "Electricity";"Magnetism"; "Waves of Sound and Light"; and "Hands-On Chemistry." (JRH)
Presents an experiment designed to give students some experience with photochemistry, electrochemistry, and basic theories about semiconductors. Uses a liquid-junction solar cell and illustrates some fundamental physical and chemical principles related to light and electricity interconversion as well as the properties of semiconductors. (JRH)
Chemistry, Demonstrations (Educational), Electricity, Energy, Heat, High Schools, Laboratory Procedures, Light, Science Activities, Science Education, Science Instruction, Secondary School Science, and Teaching Methods
Recommends using dramatic demonstrations on the energy in chemical systems as an audiovisual adjunct to lectures and laboratory sessions. Lists materials needed and provides procedures including safety tips for various experiments to produce chemical light, heat, and electricity; and concludes with hints for preparation/rehearsal. (JM)
Journal of Chemical Education, v66 n6 p510-11 Jun 1989.
Chemistry, College Science, Electricity, Higher Education, Instructional Materials, Light, Overhead Projectors, Physics, Science Activities, Science Equipment, Science Experiments, Science Instruction, Science Projects, Teaching Methods, and Visual Aids
Presents two demonstrations using the overhead projector: (1) describes how to build a projecting voltmeter and presents uses for the classroom; and (2) investigates the color of fluorescent solutions by studying the absorption and transmission of light through the solutions. (MVL)