Background:
Science education research emphasizes the crucial role of textbooks in students’ acquisition of scientific knowledge. The aim of the study is to explore the distribution and instructional functions of diagrammatic representations contained by primary textbooks and their accompanying workbooks.

Material and methods:
Diagrams from twenty science textbooks and workbooks were classified, coded and analyzed. Descriptive statistical analysis was performed. A one-way ANOVA test was performed to check if there are any distributional differences between textbook and workbook.

Results:
Great amount of diagrams have been used in the primary level of science teaching. On average, there are about 2.2 diagrams used in the textbooks and 2.0 diagrams in the workbooks for the purposes of explaining, presenting or evaluating the scientific domain. Workbooks tend to include more charts and graphs that may be used as a tool to examine learners’ conceptual learning, especially when arithmetic calculations and association between variables are involved.

Conclusions:
This study provided an approach for researchers interested in exploring usage of diagrams and other illustrations in science learning materials.