MIT’s Edgerton Center holds free Science on Saturday programs approximately monthly during the school year for elementary, middle, and high school students — as well as their parents and teachers.  Each is a fun, one-hour, interactive presentation beginning at 10AM in MIT’s Kresge Auditorium, 48 Massachusetts Ave. in Cambridge.  Kids under 12 must be accompanied by an adult. No pre-registration is necessary but seating is limited and first-come, first-seated.  The upcoming programs are March 4: Chemistry and April 1: How the Internet Works.