Visualizing Program Behavior with a Ball and Pipes for Computer Science Unplugged

Computer science unplugged (CS unplugged) is a method of teaching computer science and computational thinking. The aim of our study is to illustrate program behavior and to prevent confusion about the program stack through visualization. To facilitate recognition, we used a toy consisting of a ball, pipes, and magnetic panels. The ball represents which line of code is executed, similar to the program counter. To demonstrate the feasibility of the proposed method, we present three examples based on the proposed method. The examples are necessity of loop to wait user input, necessity of loop to keep program running, and software testing. We conducted an experiment with nine participants to evaluate the effectiveness of the proposed method. The result suggested that the proposed method is expected to be effective.