Image via WikipediaLibraries are not the only places to find reference materials. There are many different online encyclopedias, dictionaries, guides, and fact books that can be used for free on the Internet. Here are 20 online fact checkers and reference books that are freely available to everyone:
Gray's Anatomy of the Human Body - This online reference book provides an in-depth look at the human body. Gray's Anatomy features more than 1,000 engravings and illustrations.
Encyclopedia Smithsonian - The Encyclopedia Smithsonian offers 1.9 million records--from art to zoology. This online encyclopedia also links to more than 180,000 videos, images, and sound files.
The World Factbook - The CIA provides this online fact book with resources on government, history, economy, people, communications, transportation, and military. The World Factbook is also a great reference for maps, flags, and fun facts.
The Farmer's Almanac - This almanac has been providing information to people since 1792. The Farmer's Almanac offers useful information on weather, gardening, astronomy, and food.
Merriam-Webster Dictionary - This online version of the famous dictionary offers definitions, pronunciations, and information on word origins. Merriam-Webster also features a variety of other references, including a thesaurus, encyclopedia, and medical dictionary.
World Book Encyclopedia - World Book Encyclopedia has been providing reference material for children and adults since the early 1900s. This encyclopedia features accurate facts on history, people, events, and more.
Brewer's Readers Guide - The Brewer's Readers Guide offers reference material for poems and well known tales. This is a great reference for finding information about plot lines and quotes.
Encyclopedia Britannica - This online encyclopedia offers information on every topic imaginable through articles, videos, images, and biographies.
Roget's Thesaurus - Roget's Thesaurus is a well known resource for increasing the flow of words in writing. The online version of this reference features an easy-to-use search engine.
Wolfram Mathworld - This comprehensive online math encyclopedia provides information on everything from algebra to topology. Wolfram Mathworld is updated daily and carefully maintained to provide the latest mathematic techniques.
RefDesk - The RefDesk is an Internet fact checker with search engines, news headlines, dictionaries, literature, and other useful resources.
Virtual Reference Shelf - The Virtual Reference Shelf features links to information on everything from abbreviations to statistics. This site is a great place to find the best links to all sorts of factual information.
FactFinder - This U.S. Census Bureau tool offers factual information on housing, population, economic, and geographical data.
Encyclopedia of Life - This online encyclopedia offers scientific information on every species on earth. The Encyclopedia of Life includes both text and images.
Infoplease - Infoplease provides answers to factual questions on a wide variety of subjects. This informative site also features encyclopedias, summer guides, almanacs, dictionaries, and timelines.
John Hopkins Medical Desk Reference - This medical site provides links to comprehensive information about medical conditions and illnesses.
Artcyclopedia - The Artcyclopedia offers facts about artists, news, history, and movements in art. The site also links to more than 100,000 sources of factual art information.
American Museum of Natural History - The American Museum of Natural History is a great place to find factual information about anthropology, astronomy, biology, natural science, and paleontology.
Library of Congress - The largest library in the world, the Library of Congress offers several resources for checking historical facts.
Med Bio World - Med Bio World is an online medical fact checker with journal articles, databases, dictionaries, and directories. This is an excellent site for finding up-to-date medical facts and information.