Air Force Cadet Victor Lopez demonstrates a hybrid rocket engine for kindergarten-second grade students Feb. 22 at Evans International Elementary School in Falcon School District 49. More than 50 cadets arrived from the U.S. Air Force Academy to explain careers in science, technology, engineering and mathematics. Lopez, who plans to begin pilot training this summer, majors in astronautical engineering, one of six academic concentrations covered during the school's STEM Day. The other five were physics along with mechanical, electrical, civil and aeronautical engineering.