Hand-drawn classroom representations of scientific phenomena are typically sketchy and are neither reusable nor distributable.
Dynamic phenomena require multiple images to indicate time progression, and can be difficult to interpret.
Classroom representations are often difficult to reproduce by students.
Digital media provide a means to illustrate complex structures and motions, using:
They can help bridge the gap in student understanding.
Digital images and animations are examples of learning objects that are commonly viewable by any computer.
Such learning objects are reusable and improveable.
The World-Wide Web can integrate learning objects together with text and other media, and distribute them to the lecture hall or to students in their dorm rooms.
The portability of these learning objects also means that they can be easily shared with other educational institutions.
Mathematica can be used to create scientifically realistic learning objects.
The planets have circular or elliptical orbits, depending on their "tilt".
The light beam has a hyperbolic path.
The background image of this presentation is the Crab Nebula, which has a pulsar at its center.