On Friday night, CBS will air “Teach,” Davis Guggenheim’s third documentary on education in America. It was the second, “Waiting for Superman,” that earned him the ire of public school teachers everywhere for its endorsement of charter schools and demonization of unions. It appears Guggenheim took the concerns of educators to heart. “Teach,” a much-less combative film, focuses on an inspiring message we can all agree on: Great teachers make great schools. The film follows four teachers as they work to reach their students, receive advice from their principals, prepare their lesson plans and receive reviews. “Teach” airs on CBS on Friday, Sept. 6 at 8 pm eastern.