Quantitative and qualitative data were collected to assess the effects of an extracurricular science program on students' interest and learning about biology. 184 students in grades 3, 4, and 5 participated in a 6-week curriculum involving hands-on biology activities in a laboratory setting in an elementary school. A focus in separate units each week, such as the study of fossils or animal coverings, was supported by (a) creation of portfolio artifacts and open-ended work-sheets, (b) inquiry-guided explorations of laboratory equipment and experiments, and (c) socially assisted learning provided by college students who served as docents in the lab. Effects of these experiences were assessed before and after the program with an attitude survey and a test of scientific problem solving. There were significant increases in students' interest in science and significant improvements in their problem-solving skills at all grade levels. Girls reported more positive attitudes about science and had higher problem-solving scores than boys. Case studies of 18 students revealed that most students were highly motivated to use the docents, peers, and classroom resources to create their individual projects displayed at "Family Biology Night." Interviews with 3 teachers provided additional support for the benefits of the intervention. The project demonstrated motivational principles of effective instruction and illustrated how museums, schools, and universities can collaborate successfully.