Cockburn, A.Greenberg, S.2008-02-272008-02-271995-03-01http://hdl.handle.net/1880/45953This paper describes the evolution and on-going development of TurboTurtle, a dynamic multi-user microworld for the exploration of Newtonian physics. With TurboTurtle, students can alter the attributes of the simulation environment, such as gravity, friction, and presence or absence of walls. They can also manipulate the "turtle" (a movable ball) directly. Students can adjust its position, velocity and mass; change its kinetic and potential energy; and apply a force to it by strapping a rocket to its back. Students explore the microworld by manipulating these parameters, and learn concepts by studying the behaviours and interactions that occur. TurboTurtle has gone through three major evolutions. It began as a rudimentary command line extension to Logo, and became a dynamic simulation environment driven by a graphical user interface. Most recently, TurboTurtle has become "group-aware", where several students, each on their own computer, can simultaneous control the microworld and gesture around the shared display. In this final version, teachers can add structure to the group's activities by setting the simulation environment to an interesting state, which includes a set of problems and questions. The rationale behind the major design decisions in each step are presented. We also discuss the technical aspects of making TurboTurtle group-aware with a groupware toolkit called GroupKit.EngComputer Scienceunknown1995-551-310.11575/PRISM/30777