Physics Reference Desk
CODATA Values of the Fundamental Physical Constants
Here you will find the most accurate value known for the Planck constant (or any other physical constant), from NIST (the National Institute of Standards).
The Data Analysis BriefBook
A condensed handbook, or an extended glossary, covering subjects in statistics, computing, analysis, and related fields. - From CERN
Evaluated Nuclear Structure Data File
Query a database for nuclear data.
Guide for Using the International System of Units (SI)
The right way to use metric units, from NIST (the National Institute of Standards).
Periodic Table of Elements: Los Alamos National Laboratory
The Chemistry Division's Periodic Table describes the history, properties, resources, uses, isotopes, forms, costs, and other information for each element.
Table of Nuclides
An online version of the standard chart for tracing radioactive decay paths. You can zoom in on an area and then pull up nuclear data on a particular isotope.
Unit Conversion Calculator
Explore key information about the chemical elements through this periodic table
X-ray Properties Periodic Table
A periodic table that brings up x-ray properties of the elements.