Framingham State University’s Christa McAuliffe Center will hold its fourth annual Science on State Street festival on April 21, 10AM-3PM, in the parking lot of FSU’s O’Connor Hall (map).  It’s free and open to all ages, with hands-on activities (in biology, chemistry, physics, food science, robotics and engineering), presentations by FSU faculty and invited scientists, conversations and performances that explore the interaction between science and the arts, over 30 exhibiting organizations, and planetarium programs. The keynote event, Exploring Mars’ Past, will be at noon. For more information, see these FAQs or email cmc@framingham.edu.