How do children solve force and motion problems in computer simulations without explicit knowledge of the underlying physics? This question was addressed by saving the keystroke input of 19 sixth-grade children in computer memory as each interacted with a simulated, frictionless object using Logo turtle-graphics. The keystroke sequences were first used to determine subject performance on the gamelike features of the simulation. A second analysis used the Newtonian structure of the program to investigate alternative methods for controlling turtle velocity. Five boys and five girls were interviewed during the simulation concerning the perceived relationship between keyboard input and turtle behavior. Subjects who could clearly state some keyboard effects did not score high on either computer analysis, yet achieved the most general solutions of the computer problem. They did so by exploring turtle behavior under a greater variety of conditions than the subjects who achieved partial solutions. For the successful subjects, the turtle was related by analogy to useful information from existing conceptions of motion.