Using Chalk Sticks to Illustrate How Surface Area Affects Reaction Rate

This paper reports on reactions of chalk sticks with acids to illustrate the effect of surface area on reaction rate. Both qualitative and quantitative illustrations are described, with a focus on initial rates of reaction. A lesson was developed based on the illustrations, and statistical analysis showed that the lesson helped with second semester general chemistry students’ understanding of surface area. Students also largely agreed that the lesson helped with their understanding of surface area and reaction rate.