Textbooks are one of the primary sources for students to obtain knowledge, so they should
present accurate knowledge through textual and visual representations. The goal of the
current study is to examine the representations in middle school science textbooks based on
the diagram coding scheme to find out a general picture of how representations used in the
science textbooks over the fifteen years. The sample consists of 6247 representations from
twelve middle school science textbooks (four each of sixth, seventh, and eighth grades) from …