BOSTON MA. 02/20/13: SCHOOL VACATION WEEK, children enjoy the Museum of Science this week off from school. Young scientist Chase O'Donnell ( cq) from Milford listens about a 300 lbs meteorite part of a 300,000 ton meteorite that crashed into an Arizona desert 50,000 yrs ago at the Science in the Park exhibit. ( David L Ryan/Globe Staff Photo ) SECTION: METRO TOPIC stand alone photo