This document examines how a unit on model rockets, designed to be a "hands-on" activity within the "Mission to Mars" curriculum that was implemented in the Nashville (Tennessee) area middle schools, has been used to investigate children's understanding of experimentation. A literature review explores some of the traditional constraints placed on children in the field of science education and describes the development of the model rocketry unit in the "Mission to Mars" curriculum. The study participants were 23 fifth- and sixth-grade students in a summer school classroom. Each student was interviewed individually regarding the objectives of the model rocket activity, especially building the winning model rocket design as opposed to a more comprehensive view of the purpose of the experiments. Additional questions addressed students' understanding of comparisons. Over the course of the interviews, many students seem to have understood the importance of comparison, and a majority were able to see their conclusions applying not only to their own model rocket design but to rockets in general. By the final interview, 15 of 16 students stated that studying models made of cardboard and plastic were relevant for studying real rockets, and almost the entire class was able to present realistic modifications to the original experiment. Figures on student interview data are attached as well as a copy of the request for design plans from the Office of the Training Director. (Contains 35 references.) (ND)