There is increasing interest in collaborative arrangements between schools and community scientists to enhance student engagement with learning. We describe research in which we identify a wide range of such collaborations in Australia, and investigate through interviews with community participants their perspectives on the purposes of collaborations, on the outcomes, and the factors affecting success. We identify challenges with communication, with curriculum and with organisational arrangements that need to be considered in setting up collaborative partnerships, and argue the importance of having a teacher acting as a broker to bridge between the school and scientific communities of practice, if these challenges are to be met.