College of San Mateo will host a free Family Science Day on Sept. 26, with hands-on experiments, planetarium shows, a NASA keynote and rooftop stargazing.

The event, one of the college's longest-running community programs, spans two sessions: 11 a.m. to 5 p.m. and 7 to 11 p.m. No registration is required, according to the college.

Mohsen Janatpour, a College of San Mateo physics professor, created Family Science Day in 2006 to introduce young people to science through tangible experiences, marking two decades since it began.

"That's exactly what the College of San Mateo's Family Science Day event stands for, and it's why I've devoted much of my educational journey to it," Janatpour said in a statement.

The daytime program starts at 11 a.m. in the CSM Library and Makerspace, Building 9, where visitors can watch 3D printers and laser cutters in action, paint light-up miniature planets and explore vintage technology. At 1 p.m., walk-in science workshops open in the Science Building, Building 36. STEM faculty, students and community partners lead stations covering electricity, magnetism, fossils, human anatomy and solar telescope viewing.

Admission is free.

Free planetarium shows run hourly from 1 to 5 p.m. CSM Fire Technology students take over the Plaza of the Sun from 3 to 4 p.m. for "A Day in the Life of a Firefighter." Visitors get an up-close look at firefighter skills and a chance to spray water from a fire hose.

The evening shifts to the CSM Theatre, Building 3, where doors open at 7 p.m. At 7:30 p.m., Dr. Brian Day, a staff scientist at NASA's Solar System Exploration Research Virtual Institute (SSERVI), delivers the keynote lecture "The Active Moon." Day's talk explores evidence that the Moon may be more geologically active than scientists once believed, including seismic and volcanic activity that could affect plans for a sustained human presence on the lunar surface.

Day leads SSERVI's lunar and planetary mapping work and previously served as outreach lead for NASA's LCROSS and LADEE robotic lunar missions.

A reception follows from 8:30 to 9 p.m. in the Theatre Lobby. The night wraps up with rooftop stargazing and live music from 9:15 to 11 p.m. at CSM's rooftop observatory in the Science Building.

The San Mateo County Astronomical Society and CSM's Math/Science Division sponsor the event. The full schedule and campus map are available at collegeofsanmateo.edu/familyscienceday.