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The Physics Classroom is an online interactive tutorial of basic physics concepts. The lessons use an easy-to-understand language to present common physics principles discussed in a first-year high school physics course.

HowStuffWorks Science has explanations and colorful illustrations related to earth science, life science, and other wonders of the physical world.

The goal of this free online learning center is to help high school students prepare for comprehensive exams in English, math, global history, U.S. history, earth science, biology, chemistry, and physics.

Infoplease.com, a free, authoritative, and respected reference for Internet users, provides a comprehensive encyclopedia, almanac, atlas, dictionary, and thesaurus. Infoplease.com contains facts on all subjects including sports, entertainment, techno...

Online Dictionary - Multiple dictionaries including: English dictionary, medical dictionary, legal dictionary, financial dictionary, computer dictionary, thesaurus, dictionary of acronyms and abbreviations, dictionary of idioms, thesaurus, Columbia e...

YouTube is a place to discover, watch, upload and share videos.

Definition of word from the Merriam-Webster Online Dictionary with audio pronunciations, thesaurus, Word of the Day, and word games.

Explore the updated online encyclopedia from Encyclopaedia Britannica with hundreds of thousands of articles, biographies, videos, images, and web sites.

Eric Weisstein

Free Homework Help Videos in Math (Algebra 1-2, Geometry, Trigonometry, Precalculus, Calculus) & Science (Physics, Chemistry, Biology); SAT, ACT, AP & PSAT