How Stuff Works
Marshall Brain's How Stuff Works has sections for parents and students. Supercategories include internet and technology, science, health, entertainment, transportation, machines and just "cool stuff". A really great site to visit.

How things work
Site created by a Professor of Physics at the University of Virginia. Explains the "physics of everyday life" in easily comprehensible terms.

Know What?
Questions and answers provide examples of scientific principles at work in everyday life, and explain why things are the way they are.