Reported is a study to ascertain whether or not the open-ended laboratory activities in the Earth Science Curriculum Project (ESCP) program could be learned as effectively by self-directed students and to ascertain students' attitudes and interest toward learning science through a laboratory-block discovery approach. Ninety-seven junior high students enrolled in the ESCP program were involved, randomly assigned to either a control or experimental group and then subdivided into two four-week sessions for scheduling purposes. The 48 students in the control group were teacher-directed and the block was taught from an inquiry approach, utilizing 255 minutes of formal classroom instruction. The 49 experimental group students completed the block as a self-directed independent project. These students had the same time allotment. Lorge-Thorndike IQ scores, posttest scores, an attitude inventory, and student questions comprised the data collected. Analysis of data showed no significant difference on cognitive domain between the two groups. There was no significant difference shown in achievement as measured by the posttest nor in the interest shown toward the lab block. Ninety-six percent of all the students did state a high interest in working with lab block materials. There were no differences between the degree of insightfulness of questions asked by teacher-directed students and self-directed students. (Author/EB)