Computers are used with increasing frequency to deliver and enhance instruction in science. The impact of such experiences on students has not yet been extensively investigated. In particular, there are little data on what students learn indirectly about computers. A number of studies have examined the effect of computer use upon attitudes toward computers, but few have assessed the impact of computer use upon cognitive computer literacy; i.e., student knowledge about computers. We designed an experiment to investigate the impact of a brief computer assisted instruction (CAI) experience on the attitudes, beliefs, and knowledge of different types of students. A 20–30 minute science lesson on water pollution was administered to approximately 350 students by APPLE II micro-computers. Comparison of pretest with post-tests and tests six months later reveal some important impacts of exposing students to CAI for science instruction.