Scientists and Engineers in the Middle School Classroom

tion, hypothesis testing, and theory development to explain natural phenomena (McCain and Segal 1988). It is a way of knowing, a way of figuring out how the world works, a habit of mind that leads scientists to ask again and again, How do we know this phenomenon is true? (AAAS 1993). A principal objective of school science should be to give students the knowledge and experience they need to understand the work being carried out by scientists (Karplus and Thier 1967), to behave as scientists do in their pursuit of scientific knowledge (Parker and Rubin 1966; National Center for Improving Science Education 1992). Thus a science curriculum cannot be grounded on content alone, but must include the discipline processes that help students infer, synthesize, generalize, predict, and solve problems (Parker and Rubin 1966). One way to promote these processes is to invite real scientists to co-teach in middle school science