The life story of Jules Antoine Lissajous, the 19th century French physicist who did pioneering work on the properties of sound waves. Lissajous also created the first harmonograph, which allowed vibration patterns to be recorded on paper.

This is the Chapter One Challenge for the textbook Active Physics.

Discusses the feasibility of alternative energy sources, specifically Nuclear Fission and Hydroelectricity. Describes each technique, its cost and environmental impact.

A discussion, with sample equations, of the travel of a cart down an inclined plane. Includes discussion of relevant topics: potential energy, coefficient of friction, etc.

We owe a lot to artificial light, because it enables us to see in places that light normally would not reach. However, it is also hurting us in the form of light pollution, which jeopardizes our health, our planet, and our progress as a species.

A listing of Edwin Hubble's astrophysics discoveries plus other discoveries of the 20th century. Plus, a discussion of end-of-the-universe theories.