An Overview of MaxwellWorld

MaxwellWorld has been designed to enable the examination of the nature of electrostatic forces and fields, to aid students in understanding the concept of electric flux, and to help them empirically discover Gauss's Law. MaxwellWorld occupies a cube approximately one meter on a side with Cartesian axes displayed for convenient reference. The small size of the world produces large parallax when viewed from nearby, making its three-dimensional nature quite apparent. Menus and the 3-Ball are used for interaction in this world.

Unlike NewtonWorld's menus, the menus in MaxwellWorld are attached to the left wrist just as a wristwatch would be (for left-handed users, the menu location can be on the right hand). This allows the menus to be removed from the field of view, but keeps them immediately accessible, since users always "knows" where their hands are located. The index finger of the user's graphically depicted right hand is used to select menu items, and the 3-Ball button is depressed to execute a selection. Executions are confirmed by audible chimes. Navigation in MaxwellWorld is accomplished by selecting the navigation mode, pointing the index finger in the desired direction, and depressing the mouse button.

Using their graphical index finger, students can place both positive and negative charges of various relative magnitudes into the world. Once a charge configuration is established, the force on a positive test charge, electric field lines, potentials, surfaces of equipotential, and lines of electric flux through surfaces can all be instantiated, easily observed, and controlled interactively. See Figure 1. For other images from MaxwellWorld, please visit our MaxwellWorld Images page.

Figure 1. An electric field in MaxwellWorld.

For example, the tip of the index finger can be attached to a small, positive test charge, and a force vector associated with the charge depicts both the magnitude and direction of the force of the test charge (and, hence, the electric field) at any point in the workspace. A series of test charges can be dropped and used to visualize the nature of the electric field throughout a region.

In a like manner, an electric field line can be attached to one of the charges and to the index finger. A student can then move his or her finger to any point in the workspace and see the field line that connects that point to one of the charges. MaxwellWorld can also display many electric field lines to give students a view of the field produced by a charge configuration. In another mode of operation, the tip of the index finger becomes an electric potential meter that, through a simple color map and a "=" or "-" sign on the finger tip, allows students to explore the distribution of potential in the world. Actual values of the potential can be acquired by interrogating a point; digitized speech then provides an audible numerical value.

Via the production of a Gaussian surface, the flux of the electric field through that surface can be visually measured. Spherical surfaces (Gaussian or equipotential) can be formed anywhere in the workspace by using the index finger to anchor the center of the sphere and then define the initial radius of the sphere. Upon activation, the surface grows from the selected radius terminus until a closed surface is formed. In the case of equipotential surfaces, the electric forces at any point on the surface can be shown as a color mapped onto the surface at that point. A point on the surface can be "grabbed" to expand or shrink the surface's radius, and its anchor can be moved at will. During all of these activities, the underlying physical simulation updates all physical parameters (force, field lines, and potential). For more information about MaxwellWorld or Project ScienceSpace, please visit the Research Studies web page.