A gas pressure gauge has been constructed for use in a student experiment involving the law of atmospheres. From pressure data obtained at selected elevations the average mass of air molecules is determined and compared to that calculated from the molecular weights and percentages of constituents to the air. (Author/BB)

Describes some undergraduate laboratory experiments on thermoanalytical techniques which deal with both organic and inorganic compounds. (GA)

Describes a modified experiment to measure the internal resistance of an energy source, where a small resistance is connected in series with the source. (GA)

Exercises are presented for classification of marine algae on the basis of biochemical characteristics such as pigmentation, cell wall components, and food storage products. (BB)

Establishes the extent to which practical work in South African high schools varies with respect to factors such as gender of student, type of school, medium of instruction, and examination board. Investigates the relationship between experience of experimental work and pupil attainment as measured by matriculation grade. (Author/GA)

This experiment uses a nine-chambered plexiglas unit to facilitate rapid construction of galvanic cells and measurement of cell voltage. Using this procedure, a pair of students can construct and obtain the cell voltages of two precipitation cells, three concentration cells, and six redox cells in 30-40 minutes. (BB)

The observation of soap bubbles in a beaker of carbon dioxide gas helps students to feel the pleasure that comes from understanding nature, from applying that understanding to real problems, and from making unexpected discoveries that yield to analysis. (Author/BB)

Describes an experiment in which a point source of light, when viewed through a cylindrical tube having reflecting inner walls, appears as a series of sharply defined rings, due to the multiple reflections from the inner walls of the tube. ( GA)

Shows that when positions annihilate in solid materials the energy distribution of the annihilation gamma rays is much broader than that of a 0.511-Mev gamma peak. This broadening is caused by the momentum distribution of the electrons in the material. (Author/GA)

Describes an experiment for estimating molecular size and Avogadro's number. Uses the diffusion length of iodine in air at 100 degrees Celsius as a function of time, and the change in volume of a small quantity of carbon dioxide as it goes from the solid to the gaseous state. (GA)

Presents four simple laboratory procedures for: preparation of organometallic compounds, a realistic qualitative organic analysis project, a computer program to plot potentiometric titration curves, and preparation of stereoscopic transparencies. (SL)

Describes an organic chemistry laboratory exercise which uses thermochromic compounds to study the thermodynamic effect of temperature on chemical equilbrium. (SL)

Describes the apparatus and procedures for constructing simple AM radio circuits with a minimum of electronic components. (SL)

Describes the apparatus and procedures for conducting a simple speed of light experiment in an average laboratory using a laser source, a rotating mirror, and an oscilloscope. (SL)

Describes a series of polarography experiments using commercially available pulse polarography instruments. (SL)