The Cass County Extension Service is inviting youngsters who have completed 4^th through 8^th grades to participate in a STEM Explore day the that YMCA in Atlantic on Thursday, June 27th.  STEM stands for science, technology, engineering and math.  Cass County Extension Program Coordinator Kate Olson says the youngsters will participate in several hands-on projects.   The event begins at 9:00 am and will be finished by 3:00 pm.  Olson hopes to open the eyes of children to the opportunities in the sciences.   The event is free, but registration is required by the end of the day Tuesday, June 25^th.  Lunch, snacks and a t-shirt will be provided.  Registration is limited to 50 and forms are available at the extension office or the YMCA.