Discusses simple interval timers for microcomputers, including (1) the Jiffy clock; (2) CPU count timers; (3) screen count timers; (4) light pen timers; and (5) chip timers. Also examines some of the general characteristics of all types of timers. (JN)

ExCELS is a program that supports teachers interested in the use of computer interfacing at the secondary school level. This paper describes an ExCEL-based course developed for science education majors, presents an overview of interface apparatus and how it is used in schools, and gives examples of experiments performed. (LZ)

Described is a LOGO computer program that enables students to investigate the relationship between a digital number and the resistance in a variable resistor used to generate that number. Likewise, actual temperature readings and the corresponding resistance within a thermistor can be used for data gathering and subsequent analysis. (JJK)

Explains the operation of five relative humidity sensors: psychrometer, hair hygrometer, resistance hygrometer, capacitance hygrometer, and resistance-capacitance hygrometer. Outlines the theory behind the electronic sensors and gives computer interfacing information. Lists sensor responses for calibration. (MVL)

Reports on a study into the effectiveness of implementing an interactive videodisc science lesson on titration into a high school science program. Describes the titration lesson and the equipment used in two chemistry classes. Results were generated from achievement and attitude instruments, along with observational data. (TW)

Describes the functioning of temperature transducers, or thermistors. Discusses the interface connections between thermistors and the game-port of several kinds of microcomputers. Demonstrates how to construct a thermistor probe and suggests several applications of the use of such probes in various scientific experiments. (TW)

Discusses various types of transducers and explains the use of a photoresistor in sensing light. Describes various hardware and software combinations which can be used with photoresistors in science laboratory experiments. Presents general applications of this instrument in light-meter, solarimeter, and colorimeter experiments. (TW)

Discusses how computers can be applied in the science laboratory. Describes the hardware and software associated with the laboratory interface system. Outlines a three-and-a-half-day workshop to train secondary science teachers to apply computer interfacing in their laboratories. Lists 5 references. (YP)