Visual aids—films, still pictures, models, bulletin boards, and so on—are among the most useful tools in education, but they do not teach without intelligent planning and use (Glenn O. Blough and Albert J. Hugget, Elementary School Science and How to Teach It [New York: Dryden Press, 1957], pp. 33–34). Bulletin boards can play an important role in today's mathematics program. However, a bulletin board, if it is to be successful in achieving its purpose, must gain and be worthy of the class's attention.
Science for Our Children. A Report of the Committee for the Study of the Teaching of Elementary School Science in New York State.