Simple Machines
- Games challenge you to identify different types of simple machines.
- http://www.edheads.org/activities/simple-machines/

Simple Machines Learning Site
- An overview of the six basic types of simple machines with pictures and student drawings.
- http://www.coe.uh.edu/archive/science/science_lessons/scienceles1/finalhome.htm

Animated Engines
- Animated pictures explain the inner workings of a variety of steam, stirling, and internal combustion engines.
- http://www.keveney.com/Engines.html

The Secret Life Of Machines
- Drawings and explanations to common machines and how they work.
- http://www.secretlifeofmachines.com/