Procedures are provided for a test that (1) demonstrates principles of derivatization with 2,4-dinitrophenylhydrazine; (2) is a thin layer chromatography experiment that visually demonstrates separation of colored compounds of different polarities; and (3) introduces microscale experimentation to students in sophomore organic chemistry…

The separation of derivatives of aliphatic compounds (2,4-dinitrophenylhydrazones) is used to introduce methods and techniques typically employed in thin layer chromatography and to provide a clear illustration of chromatographic principles in general. Procedures used in the separation are presented. (JN)

Although infrared spectroscopy is used primarily for qualitative identifications, it is possible to use it as a quantitative tool as well. The use of a standard curve to determine percent methanol in a 2,2,2-trifluoroethanol sample is described. Background information, experimental procedures, and results obtained are provided. (JN)

Describes a complementary pair of radiochemistry experiments for instruction of isotopic dilution analysis and secular equilibrium. Both experiments use the readily available cesium-137 nuclide and the simple precipitation technique for cesium with the tetraphenylborate anion. Procedures used and typical results obtained are provided and…

Background information, experimental approach, materials needed, procedures used, and typical results obtained are provided for genetic engineering experiments. The course in which these experiments are performed is also described. (JN)

Describes an experiment which allows students to identify the nature of the time-course for chymotrypsin and to obtain mechanistic information on the two kinetic phases in terms of their concentration dependence. Also describes the computer simulation (available from the author) used in the experiment. (JN)

Background information, procedures used, typical results obtained, and calculations are provided for a short (4-6 hours) kinetic experiment which includes different methods both in performance and in analysis of the results. The experiment can be modified and extended depending on the level of students and the available laboratory time. (JN)

Describes a typical presentation in which slime is prepared for young, concrete operational students. Includes the procedures used and a summary written by a fourth-grade teacher after completing the slime experiment with her class. (JN)

Background information, list of materials needed, and procedures used are provided for a demonstration involving the transformation of a hydrophobic liquid to a partially hydrophobic semisolid. Safety considerations are noted. (JN)

An updated version of "Mr. Wizard" is returning to television three times a week on Nickelodeon, the cable network for children. Highlights the career of Don Herbert (who is Mr. Wizard) and his experiences with "Mr. Wizard" television programs. (JN)

Provides procedures for the study of osmosis and anthocyanin pigments utilizing wet mount techniques with purple onion. Suggests several activities using this preparation. (JM)

Discusses the physics behind making ice cream in a hand-cranked ice cream maker. Ingredients in the maker are cooled and hardened by a bath of ice, water, and rock salt. Several experiments to investigate the variables involved in preparing the ice cream (and related desserts) are included. (JN)

Presents (in the form of a dialogue between a student and teacher) an alternative method of using the Fine-Beam Cathode-Ray Tube to obtain the value for the specific electronic charge e/m. (JN)

Describes a five-period experiment which: (1) integrates preparative and analytical techniques; (2) utilizes a photochemical reaction that excites student interest both from visual impact and as an introduction to photoinduced processes; (3) provides accurate results; and (4) costs less than $0.20 per student per laboratory session. (JN)

Although polarimeters that illustrate rotation of plane-polarized light by chiral solutions have been previously described, the polarimeter described in this paper has certain advantages when used in conjunction with an overhead projector. Instructions for constructing this polarimeter and its use in demonstrating the optical activity of sugars…