Scholars gain an insight into the relative size of planets and distance between inner and outer planets with the help of informational text, a data table, and a series of four questions.  

An outstanding page describing Kepler's three laws of planetary motion.

This study guide on gravitation covers some key vocabulary, Kepler's Laws of Planetary Motion, and orbiting bodies or satellites. Includes important equations. It is available for download with free registration.

The University of Virginia provides a continuation of a lecture given on astronomer Johannes Kepler, this lecture covers his different works within the field of astronomy.

The University of Virginia provides notes from a lengthy lecture given on the life of Johannes Kepler. This site has GREAT information and is easy to understand.

This site from Open Source Physics offers a file with a simulation of Kepler's theory of planetary motion, tested with the Earth rotating around the sun and another planet of the user's choosing. The download requires Java.

An exhaustive biographical account of Johannes Kepler. Describes at length his upbringing, childhood, education, personality and scientific endeavors. Focus is on his development of a cosmological model and the laws of planetary motion.