Reading textual and non-textual explanations in chemistry texts and textbooks - a review

Reading is an integral part of chemistry education. The language of chemistry plays a major role when reading chemistry texts and textbooks. Reading textual and non-textual explanations impact students' understanding of chemistry texts and textbooks. In our review we outline the importance of reading texts and textbooks in chemistry education. We offer different points of view to look at textbook research (conceptual, socio-historical, textual, non-textual) and reading research (readability and comprehensibility) and focus on reading research on textual and non-textual explanations. We point out two major shifts in research interests on texts, textbooks and reading: from readability to comprehensibility and from textual to non-textual explanations. We consider research from the 1950s until today and analyse literature concerning elementary, secondary and tertiary science and chemistry education. Finally, we review ideas for encouraging reading and conclude by presenting recommendations for chemistry education researchers and chemistry teachers on how to improve reading in chemistry education.