Nutzungsbedingungen AbstractTwo research studies sponsored by CILS investigated the programmes ISIs currently provide to support K-12 science education, particularly in the area of teacher professional development (PD). The first study was a large-scale survey with 475 ISIs responding about the programmes they offer schools and teachers beyond one-day field trips. A large majority of ISIs (73%) reported having one or more of these programmes, with more than half (59%) providing one or more forms of teacher PD. ISIs also reported a tendency for their programmes to be under-subscribed, and said funding was the biggest barrier to their ability to provide these programmes.A second study focused on ISI-based teacher professional development (PD) programmes, looking at whom they serve, how they are funded, and their specific programmatic elements. This study also investigated the extent to which ISI-based PD incorporates features shown to produce measurable effects on teachers' instructional practice. Researchers administered an intensive survey to over 310 ISIs with teacher PD offerings to obtain detail regarding the programming. The findings reported here indicate that the particular promise of ISI-based teacher PD is the potential to incorporate features of PD that research has shown to produce measurable effects on teachers' practice. The results from these two studies suggest that while some opportunities may be missed to leverage the strengths of the ISIs' learning environment in K-12 science education, ISIs continue to support K-12 science education in the US in important and varied ways.