Replacement of Dimensional Analysis with Proportional Reasoning in Introductory Chemistry and Its Effects on Students’ Chemistry Conceptual Understanding

Dimensional analysis is an algorithm currently in use in almost every chemistry classroom in the United States. Chemistry educators use this procedural tool in the classroom with the intention of providing students with a reliable method to solve many of the relatively simple math problems they encounter. The unintended consequence of using this algorithm is that dimensional analysis divorces conceptual from procedural knowledge and effectively produces students who are answer-getters instead of critical thinkers. Instruction that integrates both conceptual and procedural knowledge into curriculum improves students’ conceptual understanding of a topic while still equipping them with necessary skills to solve rote, mathematical problems. This study assesses the impacts of replacing instruction in dimensional analysis with instruction in proportional reasoning on students’ conceptual chemistry understanding. Results indicate that students who received instruction in proportional reasoning instead of dimensional analysis experienced significantly greater growth in the area of chemistry conceptual understanding when compared to their peers who received instruction in dimensional analysis.