Project Accelerate is a NSF-funded project aimed at helping prepare underserved high school students for the AP Physics 1 exam. The students attend schools that do not offer AP Physics 1. All Project Accelerate students are enrolled in a scaffolded small private online course (SPOC) that takes them through the physics material in an interactive way. A significant fraction of the students, including all those in the Boston area, also attend weekly 2.5-hour sessions on campus to do hands-on lab activities and recitation exercises. These sessions are led by undergraduate students who have pedagogical training. Our data indicate that Project Accelerate participants do at least as well on the AP Physics exam as similar students who take an AP Physics 1 through a traditional classroom-based course. One of the main goals of Project Accelerate is to give underserved students access to a rigorous science course, helping these students to build a solid foundation for a possible undergraduate degree in STEM. We also present evidence that successfully completing Project Accelerate makes students more likely to pursue further opportunities in STEM.