Abstract
Cooley and Reed's active interest measurement approach was combined with Guttman's Facet Design to construct a systematic instrument for the assessment of the impact of an environmental science course on students' behavior outside school. A quasimatched design of teacher allocation to the experimental and control groups according to their preferred teaching style was used. A kind of dummy control curriculum was devised to enable valid comparative evaluation of a new course which differs from the traditional one in both content and goal. This made it possible to control most of the differing factors inherent in the old and new curriculum. The research instrument was given to 1000 students who were taught by 28 teachers. Students who learned according to the experimental curriculum increased their leisure time activities related to the environmental science curriculum significantly. There were no significant differences between boys and girls and between students with different achievement levels.