This 10-chapter report presents information on the 1986 assessment of students' science performance in the province of Manitoba in Canada. The assessment was intended to provide a broad base of accurate information on the performance of grade 3, 6, and 9 students. The program of studies for Manitoba schools is designed to educate the student in science over a wide range of science goals and objectives that go well beyond knowledge of science content. Tests were developed to survey student performance on the knowledge, understanding, skills, and attitudes that form the Manitoba Science Curriculum. The student assessment included two components. A written component contained cognitive and affective questions. A performance component required students to apply science skills, knowledge of science concepts, and the ability to use common laboratory equipment and techniques. A survey of science teachers in grades 1-6 was conducted in conjunction with the student assessment to provide teacher information that would complement the student data. The results of these tests were considered in light of the 1980 Science Assessment results. Appended are a sampling design and results of the teacher questionnaire. (KR)