Simon Fraser University
Chem1 Virtual Textbook: Understanding the Units of Scientific Measurement
As part of a larger site called "Getting started in Chemistry," this site examines the units of scientific measurement with specific attention given to SI base units, SI decimal prefixes, units outside SI, and more.
Wikimedia
Wikipedia: International System of Units
Wikipedia offers detailed information on SI, or the International System of Units. Includes hyperlinked table of contents for easy site navigation.
Science and Mathematics Initiative for Learning Enhancement (SMILE)
Smile: Metrics in the Home and in the Store
In this lesson plan site, young scholars will compare SI unit (metric) measurements of common household items and their English equivalents.