VISUAL AND AUDIOVISUAL MATERIALS WERE TESTED TO DETERMINE THEIR EFFECTIVENESS IN A 1-YEAR NINTH-GRADE ALGEBRA COURSE. TESTS WERE GIVEN TO AN EXPERIMENTAL AND A CONTROL CLASS AFTER EACH UNIT TO ASSESS LEARNING. IN ADDITION, EACH STUDENT USED A POTENTIOMETER TO INDICATE THE LEVEL OF LEARNING EACH MINUTE OF THE LESSONS. ELECTRICAL SUMMATION EQUIPMENT PROVIDED A LEARNING PROFILE OF THE CLASS DURING EACH LESSON. AN ATLAS OF PROFILES WAS PREPARED TO LOCATE STRONG OR WEAK LEARNING SEQUENCES DURING CLASS SESSIONS. IT WAS NOT POSSIBLE TO PRODUCE ANY SIGNIFICANT INCREASE IN LEARNING FROM THE COURSE. HOWEVER, LEARNING DID NOT DECREASE IN THE MANNER REPORTED IN SEVERAL OTHER STUDIES OF COURSES USING VISUAL MATERIALS. DATA WERE PRESENTED IN SUCH A MANNER THAT TEACHERS AND CURRICULUM DESIGNERS MIGHT OBTAIN SUGGESTIONS ABOUT AVAILABLE AUDIOVISUAL MATERIALS AND THEIR RELATIVE EFFECTIVENESS. (JM)