Consequently, when students construct poor explanations it is difficult to tease out if students’
difficulty stems from their lack of understanding of the content or their lack of understanding of
scientific explanations. The relationship between content understanding and explanation
construction suggests that one reason the scaffolds did not appear to influence students’
explanations on the chemical reaction questions on the posttest may be because the students did
not understand the chemical reaction content well enough to demonstrate their understanding of
scientific explanations.