Although personal computers have dramatically changed our lives, over the past decade have they really changed the way we teach, particularly in the laboratory? While computers are available for classroom and laboratory use, we have observed in many secondary schools that a significant proportion of computer use is still in the drill and practice phase, with considerably less computer use devoted to simulations and hypermedia. In the laboratory, an alternative to drill and practice and/or simulation has been amply illustrated by Vernier (1986) and by Seligmann and Thompson (1989). The authors' examples illustrate how to use the computer as a laboratory tool for data acquisition and analysis.This paper describes another example of the use of the computer in the laboratory for data acquisition and analysis-specifically a method to measure the respiration rate in aquatic organisms and also to demonstrate the use of pH measurements in the introductory biology laboratory. This experiment can be carried out with a conventional pH meter and application software or hand calculations. However, it is more easily performed with a computer using a simple game port interface, a pH probe and appropriate software for analysis. The computer approach also has the following advantages: