Describes the construction and operation of an overhead projection apparatus designed to demonstrate streamline flow of a liquid. The apparatus consists of a Plexiglass tank containing water in which plates forming the cell are submerged, a constant level reservoir, an overflow device and a system for marking the flow lines with a dye. (LC)

Describes new apparatus and equipment for use in chemistry laboratories. Four new literature citations are also reported and three new chemicals. A reader's inquiry card is available for requesting more information. (CS)

Two equipment systems are described: mechanical start-stop gates for air tracks, and a large-scale magnetic induction demonstration. (CS)

Describes various uses for balloons in chemistry instruction, such as their use as stirring devices, gas reservoirs, sources of carbon dioxide, and as atomic models. (CS)

Presents the plans for constructing a mode 2 TOPS Projector-adaptor, which costs one-half that of a model described in an earlier article. The author uses a step-by-step approach to the project. (SA)

The design, construction, and operation of a solid state electrometer is described. The instrument used the case and meter movement from an obsolete commercial pH meter. The cost of materials, purchased in 1977 in unit quantities, was $60. (BB)

Describes the construction of a thermostat of double-oven design that can maintain a stability of two mdeg for several hours and can accomodate sealed-glass ampoules at elevated temperatures. (MLH)

Describes a temperature control system that can be used with a double-oven thermostat to provide two mdeg regulation over several hours. (MLH)

Discusses the contribution of 17th and 18th century instrument makers to the development and progress of science and the methods of teaching science. (MLH)

Discusses the accuracy of sundials and many factors which affect their ability to measure apparent local time. Provides directions for constructing a sundial, including how to make a universal dial. Includes background information regarding other types of sundials and descriptions of notable sundials. (DDR)