Two methods of assessing student learning of a hands-on instructional unit are compared. One method involves manipulation of concrete materials, and the other method involves manipulation of icons on a computer to solve an electric circuits problem. Sixth-grade students in an inquiry-based science program completed both assessments separated by three weeks. Results indicated that although mean performance was the same for each method, individual student performance varied considerably. Implications for use of computer simulations as an alternative to hands-on assessment are discussed.