To promote the spirit of science as inquiry, this article presents an engaging activity that capitalized on students’ interest in the homerun-hitting race between professional baseball players Mark McGwire and Sammy Sosa. Third-grade students were encouraged to challenge the first-grade students to a contest, not of hitting homeruns but of blowing cotton balls. As a result of this activity, students learned how to use inquiry to gain an understanding of force and motion and practiced science process skills such as measuring, graphing, and analyzing data.