Two schools in DeKalb County have been certified as “STEM” schools, doubling the total for the district.

Tucker Middle School became the first middle school in the state to earn the distinction, according to the DeKalb County School District. And on Friday, State Superintendent John Barge traveled to Dunwoody Elementary to announce that it, too, had joined the list. DeKalb’s Henderson Mill and Hightower elementaries were already STEM schools.

The certification means the schools teach science, technology, engineering and math in a rigorous and integrated manner. STEM schools use student-driven projects to facilitate problem solving and discovery. They also must have teacher collaboration and partnerships with business and industry, according to stemgeorgia.org.