When COVID-19 shut down in-person programs across the world in 2020, we (the National High Magnetic Field Laboratory (MagLab)) as practitioners were in unknown territory. This paper outlines the structure of a 10-week online Summer Exploration Series (SES) program along with the evaluation performed by staff at the MagLab in 2020. The goal of the SES program was to increase youth's interest in STEM and knowledge of STEM careers relevant to materials science. Each week included live and asynchronous components. All of the participants (n=86) rated the program as above average or higher, crediting the program with teaching them about new STEM careers/topics and increasing their interest in STEM. Our evaluation indicated that the live sessions, particularly those that offered more opportunities for interaction, were rated higher than the asynchronous sessions, providing evidence to the benefits of live - even if online -- sessions on increasing interest in STEM. The lessons learned through the program can inform other organizations as we continue into the new normal.