A STUDY OF THE DEVELOPMENT OF AN AUTOINSTRUCTIONAL PROGRAM IN PHYSICAL SCIENCE FOR FIRST-GRADE PUPILS WAS DESCRIBED. OBJECTIVES WERE TO DETERMINE THE EXTENT TO WHICH FIRST-GRADE CHILDREN COULD LEARN ABSTRACT CONCEPTS OF MOLECULAR THEORY AND USE THEM TO EXPLAIN EVAPORATION AND CONDENSATION, AND TO DISCOVER THE EFFICACY OF THE AUTOINSTRUCTIONAL METHOD USING A TEACHING MACHINE CALLED THE VIDEOSONIC TUTOR. IN THE FIRST PHASE OF THE STUDY, A 400-ITEM PROGRAM ON MOLECULAR THEORY WAS ADMINISTERED TO SIX PUPILS FOR 12 SESSIONS EACH. CONTROL GROUPS WERE MATCHED WITH THE EXPERIMENTAL GROUPS. RESULTS INDICATED THAT CHILDREN MAINLY LEARN SIMPLE RELATIONSHIPS. NO DIFFERENCES IN TRANSFER ABILITY WERE FOUND BETWEEN EXPERIMENTAL AND CONTROL GROUPS. ON THE BASIS OF THE FINDINGS, PROGRAM REVISIONS WERE MADE IN THE SECOND PHASE, AND THIS NEW PROGRAM WAS PRESENTED UNDER MORE HIGHLY STANDARDIZED CONDITIONS. ON A POST-TEST, CHILDREN SHOWED BETTER LEARNING THAN IN THE FIRST PHASE, BUT ABILITY TO GENERALIZE WAS STILL POOR. IN THE THIRD PHASE, ITEMS WERE REVISED AGAIN AND, IN ADDITION, A SPECIAL SET OF INSTRUCTIONS FOR THE PHYSICAL OPERATION OF THE VIDEOSONIC TUTOR WAS PROGRAMED. THE EXPERIMENTAL GROUP SCORED MUCH HIGHER ON A POST-TEST THAN DID THE CONTROL GROUP. TENTATIVE CONCLUSIONS WERE THAT (1) FIRST-GRADERS CAN LEARN ABSTRACT CONCEPTS OF MOLECULAR THEORY AND CAN USE THEM TO EXPLAIN PHYSICAL PHENOMENA OF EVAPORATION AND CONDENSATION, WITH ONE EXCEPTION--THE SUBJECTS' INTERESTS WERE HELD BY THE VIDEOSONIC TUTOR FOR A 3-WEEK PERIOD, (2) THE USE OF STILL PICTURES IN THE VIDEOSONIC TUTOR DID NOT MAKE IT IMPOSSIBLE TO TEACH CONCEPTS INVOLVING MOTION, (3) MOST OF THE SUBJECTS COULD USE PREVIOUSLY UNFAMILAR TERMS IN ADDITION TO THEIR OWN WORDS IN DEALING WITH NEW SITUATIONS, BUT SOME HESITATED IN VERBALIZING THE TERMS, AND (4) THE USE OF EARPHONES ELIMINATED DISTRACTIONS.