Children can learn about bicycle safety, see a police dog demonstration, and meet McGruff the Crime Dog at a child safety day Saturday. Officer Jeanine Matott of the Holbrook police said the event will offer checks of car seats and bicycle helmets, free helmets to children who don’t have them, and child fingerprinting. The Norfolk County Sheriff Office’s mobile command center and Holbrook police bicycles are scheduled to be on hand, and the sheriff’s office will provide hamburgers and hot dogs. “Basically we just want to do something for the kids in the community,” Matott said. The safety day, sponsored by the Holbrook Police Department and the sheriff’s office, runs from noon to 4 p.m. at Holbrook Junior-Senior High School.