Ducksters
Ducksters: Physics for Kids: Friction
Kids learn about the science behind friction including how it works as a force to slow things down, how it helps us stand, preventing friction, types, and fun facts.
Exploratorium
Exploratorium: The Science of Sports Cycling
A detailed look at the aerodynamic principles associated with cycling. Good science and even better web page design. Includes an online calculator that allows the user to calculate the aerodynamic drag and propulsive power of a bicyclist...