A BASIC computer program was written for an experiment that measures the time of a fall of a ball-bearing dropped through a measured distance. However, the timing subroutine was written in machine language. The reason for using machine language, the machine language program, hardware used, and the experiment are discussed. (JN)

Describes: (1) a microcomputer demonstration of autocatalysis; (2) a safe alternative to ethanol and methanol; (3) a simple condenser for test-tube reactions; (4) a new procedure for studying the magnetic properties of transition metal compounds; (5) plasticization of the polymer PVC; and (6) some thoughts on polybasic acids and their salts. (JN)

Describes: the chemical history of a pencil; a simple solar camera for measuring the sun's diameter; the experimental comparison of the thermal stability of metal carbonates; and the introduction of the concept of weight as a force to young children. A computer program listing on color mixing is also provided. (JN)

The emphasis on laboratory activities for science students has increased. This paper describes research that sought to determine which laboratory skills and competencies are viewed by current teachers as necessary for the preservice teacher to develop. The skills and competencies survey included 145 items in three categories (general, biological…