Short articles present ideas for demonstration equipment useful for the junior high school science: three-dimensional magnetic fields, model clocks, and smoke-ring puffers." (AL)

Describes the basic principles of setting up an aquarium and gives hints on its use as an instructional aid in elementary classrooms, both in generating biological questions and investigations and in its use in other parts of the science curriculum. (AL)

Describes the construction and operation of a quadrupole mass spectrometer for experiments in an advanced-teaching laboratory. Discusses the theory of operation of the spectrometer and the factors affecting the resolution. Some examples of mass spectra obtained with this instrument are presented and discussed. (LC)