Introductory Topics (Units, math, significant figures, etc.)
NIST units; errors; etc. http://physics.nist.gov/cuu/
Google Calculator: http://www.google.com/help/features.html#calculator
Unit Conversions : http://www.unitscalc.com/
Dictionary of Measurements: http://www.unc.edu/~rowlett/units/
Powers of Ten: http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/index.html
Old Units: http://home.clara.net/brianp/index.html
Math
Skills
Fundamental
Physical Constants
NIST Constants,
SI Units, and Error Analysis
Units and Conversions: http://www.megaconverter.com/index.html
Significant Figures http://villa.lakes.com/thompson/sigdig/
Sig.Figs., Intro: Bertrand:: http://www.umr.edu/~genchem/links.html
Stephen Lower, Matter & Measurement:
http://www.sfu.ca/person/lower/TUTORIALS/matmeas/
T. Su at UMass Dartmouth:
http://www.umassd.edu/1Academic/CArtsandSciences/chemistry/Catalyst/sf.html
Chem Team Sig Fig Rules and Practice Problems:
http://dbhs.wvusd.k12.ca.us/SigFigs/SigFigRules.html
University of Maine: http://oldblue.umeche.maine.edu/genchem/sigfigs.html
English and Foreign Names of Elements and their Meanings
http://members.xoom.com/tneleme/index.html
All about Units and Dimensions: http://www.unc.edu/~rowlett/units/index.html
Good! Scientific Notation and Measurement:
http://www.visionlearning.com/library/science/general-1/SCI1.3-measurement.htm