Children’s science vocabulary uniquely predicts individual differences in science knowledge

•Children’s productive science vocabulary predicted their science knowledge.•Science vocab was predictive over general receptive vocab and demographic variables.•This relation was particularly important among preschool and kindergarten children.•Children with larger science vocabularies drew more science elements. Science achievement gaps are a persistent social issue and are largely explained by individual differences in science knowledge before formal schooling. We were interested in whether children’s science vocabulary relates to these differences in science knowledge. This experiment examined whether children’s science vocabulary predicted their science knowledge above and beyond general vocabulary size and demographic variables. Children aged 3 to 11 years (N = 91; 59 boys) participated in-person at a laboratory within a large university in a mid-size city in the midwestern United States. The tasks that the children completed assessed general receptive vocabulary, science productive vocabulary, general science knowledge, and conceptions of science as a practice. We found that science vocabulary was the strongest predictor of science knowledge above and beyond other factors, indicating that science vocabulary production may predict individual differences in science knowledge specifically when achievement gaps emerge (β = .28). In addition, children who produced more of certain types of science words, such as size and physical property words, depicted more science equipment and language elements in their drawings of scientists. These findings suggest that learning new words may be related to conceptual development in science and that examining early science vocabulary is a key step toward fully understanding science knowledge gaps.