This study evaluated the effectiveness of the use of videodisc technology in a school system. The videodisc "Understanding Chemistry and Energy" (Systems Impact, 1987) having 20 lessons was used in Physical Science classes (grade 9) and Biology classes (grades 10 and 11) in an experimental school. It was designed to be used with a variety of classes especially classes for studying some aspects of chemistry. Printed worksheets and quizzes were also provided to the experimental classes. Because the differences in pre and posttest scores were very large for the experimental group as compared to the control group, items were analyzed by teachers to determine whether they were covered or not during classroom instruction. For the items covered a lot or some during class, there were significant differences between the two groups. (YP)