The Erudite Directory

Smarthistory (smarthistory.org)

Focus: Art history and appreciation. Smarthistory is an award-winning open educational resource that makes the history of art engaging and accessible. It offers free content curated by hundreds of leading art historians and scholars, including videos and essays on thousands of artworks from around the globe. As an NEH-funded project, Smarthistory’s mission is to open up expert knowledge about art to everyone. The site covers art movements, individual works, and themes, often in conversational videos or concise articles that are appropriate for students and lifelong learners alike. From ancient sculptures to modern paintings, Smarthistory provides authoritative context and interpretation, helping viewers around the world learn why art matters and how it connects cultures.

Heilbrunn Timeline of Art History (metmuseum.org/toah)

Focus: Global art history (museum collection-based). Presented by the Metropolitan Museum of Art, the Heilbrunn Timeline is a rich resource pairing thematic essays with art objects. Authored by the Met’s own curators and experts (art historians, conservators, scientists), it features over 1,000 scholarly essays and 7,000 cataloged artworks, organized chronologically and geographically. This free web publication is aimed at students and the public as an “invaluable reference and teaching tool” on world art history. Visitors can explore timelines of different eras and regions, then dive into well-illustrated essays that provide insight into artistic movements, styles, and cultural context. The content is regularly updated with new research and discoveries, reflecting the Met’s commitment to public education and cultural knowledge.

Chemistry LibreTexts (chem.libretexts.org)

A university-supported open-access “living library” of chemistry textbooks and resources. LibreTexts (especially the Chemistry Library) is authored and continually revised by professors and experts. It spans general, organic, inorganic, physical and analytical chemistry in multiple “bookshelves” by topic. For example, the home page explains: “This Living Library is a principal hub of the LibreTexts project…an open access textbook environment…under constant revision by students, faculty, and outside experts”. The tone is academic but free of jargon, with diagrams and examples. Since it’s open-license and hosted by universities (e.g. UC Davis), LibreTexts offers high-quality, peer-reviewed content on all major chemistry areas.

Chemguide (chemguide.co.uk)

A well-known site created by a veteran chemistry teacher (Jim Clark) to help students “understand Chemistry”. It covers advanced-high-school to early-college topics: atomic structure, bonding, thermodynamics, kinetics, organic compounds and reaction mechanisms, plus instrumental analysis. The explanations are concise and written in plain English (no student forums or marketing). For example, it has sections on atomic properties, periodic trends, A-level organic reaction mechanisms, etc. The tone is didactic but clear, making challenging topics (like equilibrium and NMR) accessible through step-by-step text and occasional illustrations. Though not updated frequently (last major revision 2017), it remains a free expert resource with minimal fluff.

MIT OpenCourseWare – Circuits and Electronics (ocw.mit.edu)

Focus A full undergraduate course (free to access) that covers the fundamentals of electrical engineering circuits. This expert-designed curriculum (by MIT professors) explains resistors, capacitors, transistors, amplifiers, and digital logic, with lecture notes, problem sets, labs and video lectures. The OCW pages summarize course topics clearly (e.g. “fundamentals of the lumped circuit abstraction… amplifiers, energy storage, time- and frequency-domain design”. The material is thorough and technical but still aimed at newcomers to electronics, making it a valuable university-level learning resource.

All About Circuits – Lessons in Electric Circuits (allaboutcircuits.com)

(Textbook & Tutorials) – A comprehensive online electrical engineering resource. It hosts “Lessons in Electric Circuits”, a free multi-volume textbook covering electricity and electronics (DC/AC theory, semiconductors, logic, digital and analog circuits). Written by engineers and updated by the All About Circuits team, the content is expert-authored and richly illustrated. The tone is formal but approachable; the textbook and accompanying articles explain concepts step-by-step (for example, detailed chapters on Ohm’s law, transistors, and op-amps). This site also offers video tutorials and worksheets, making it a one-stop shop for self-paced learning.

Encyclopedia of Earth (editors.eol.org/eoearth)

Focus: Environmental science and Earth’s natural environments. The Encyclopedia of Earth is a free, expert-reviewed collection of articles contributed by scholars and professionals on topics like ecology, climate, and geology. Written in non-technical language for a broad audience, its peer-reviewed entries provide reliable information about the Earth and how natural systems interact with society. This resource is overseen by an editorial team to ensure high quality and is continually updated by experts, making complex environmental issues accessible and educational for all ages.

All About Birds (allaboutbirds.org)

Focus: Ornithology (bird identification, behavior, and birdwatching). Created by the Cornell Lab of Ornithology’s experts, All About Birds is a free online guide to birds and bird watching. It offers in-depth species accounts, photos, bird calls, and tips from scientists to help users learn about hundreds of bird species. The site’s educational value lies in its accurate, expert-curated information presented in an engaging way, perfect for students, nature enthusiasts, or anyone curious about birds. (For example, you can explore life history details and even watch bird behavior videos, all compiled by a leading institution in bird science

British Geological Survey – Discovering Geology (bgs.ac.uk)

Focus UK government site with clear, illustrated lessons on rocks and minerals. It defines a “rock [as] a solid collection of minerals” and explains the three rock types (sedimentary, igneous, metamorphic) and the rock cycle in plain language. his expert-run portal is richly illustrated and written at a general-audience level, emphasizing mineral composition (e.g. granite’s crystals of quartz, feldspar, mica) and how Earth materials form. The tone is educational and accessible to all ages, making it a great resource on rock formation and mineral content.

U.S. Geological Survey – Minerals Education (usgs.gov)

Focus The USGS Mineral Resources Program provides free fact sheets and articles on Earth’s mineral commodities and resources. Its Mineral Commodity Fact Sheets (“easily-understood…fact sheets about important mineral commodities”) explain where each mineral comes from, its uses and importance. Although aimed at general audiences (including K–12 teachers), the content is authored by geoscientists. This expert-driven site also includes a “Mineral Resource of the Month” series, making complex topics like resource extraction and usage accessible with simple explanations.

World History Encyclopedia (worldhistory.org)

Focus: World history and cultural heritage. This non-profit site (formerly Ancient History Encyclopedia) provides easy-to-read, high-quality articles entirely for free on historical topics spanning all eras and regions. Entries are written and reviewed by historians and experts, ensuring they reflect current scholarship while remaining accessible. The editorial team carefully vets submissions, publishing only reliable content in line with academic standards. World History Encyclopedia engages readers with maps, timelines, and illustrations, aiming to improve history education worldwide and spark curiosity about our shared past.

HistoryExtra (historyextra.com)

Focus: British and world history. HistoryExtra is the official website of BBC History Magazine, featuring thousands of expertly written articles on global history topics for readers at all levels. Content on the site ranges from in-depth features on historical events and figures to Q&As and explainers, often written by academic historians or experienced history writers. The site is all-ages appropriate and richly informative, you can find anything from ancient civilizations to modern history, presented in an engaging magazine-style format. (Being tied to BBC History Magazine, it ensures scholarly accuracy while remaining accessible and interesting to general readers.

Wolfram MathWorld (mathworld.wolfram.com)

Focus: Mathematics (from basic to advanced topics). MathWorld is often called the web’s most extensive mathematics encyclopedia, created and maintained by mathematician Eric Weisstein with support from Wolfram Research. This free, reliable online resource contains over 13,000 entries explaining mathematical concepts, theorems, and proofs. Each article is written in an expert yet accessible manner, frequently with diagrams and references, making it valuable for students, educators, and math enthusiasts. MathWorld’s content is continually reviewed and updated, and it even includes contributions from the broader mathematical community, all vetted for accuracy.

Stanford Encyclopedia of Philosophy (plato.stanford.edu)

Focus: Philosophy (comprehensive coverage of philosophical topics). The Stanford Encyclopedia of Philosophy (SEP) is a highly respected open-access scholarly encyclopedia curated by Stanford University. All entries are written by PhD scholars and rigorously peer-reviewed, making it “arguably the most credible open-access source of philosophical information” on the web. With nearly 1,800 authoritative articles that are regularly updated, the SEP provides in-depth yet neutral overviews of philosophers, theories, and concepts. Its educational value is immense for both beginners and advanced readers, each article maintains academic standards while remaining free to the public. (Unlike crowdsourced sites, the SEP is edited by experts and kept up-to-date, so even complex ideas are explained with reliable scholarship

Internet Encyclopedia of Philosophy (iep.utm.edu)

Focus: Philosophy. The IEP is another free, peer-reviewed online encyclopedia of philosophical terms and thinkers. Founded in 1995, it provides hundreds of detailed articles written by professional philosophers and reviewed to academic journal standards. Articles in the IEP are intended to be understood by advanced undergraduates and general readers, not just experts, so they clearly explain philosophical ideas without oversimplifying. All content is open-access and non-profit, contributed by volunteer scholars worldwide. For students or curious readers, the IEP offers reliable insights into ethics, logic, metaphysics, and more, complementing the Stanford Encyclopedia with a readable approach to scholarly information.

NASA (NASA.gov)

Focus: Space exploration, astronomy, and Earth science. The official NASA website offers a wealth of free educational content about the universe, our planet, and technology. It includes articles, images, videos, and interactive resources created by NASA scientists and educators, making complex space science accessible to learners of all ages. NASA’s online materials range from mission updates to kid-friendly activities, all presented by one of the world’s leading science agencies (the content is authoritative and frequently updated).

Exploratorium (exploratorium.edu)

Focus: General science, human perception, and hands-on learning. The Exploratorium (a renowned science museum in San Francisco) describes itself as “a public learning laboratory” that lets visitors explore the world through science, art, and human perception. Its website provides free interactive exhibits, experiments, and engaging explanations of scientific phenomena. Curated by museum educators and scientists, the content encourages curiosity and critical thinking—aligning with the Exploratorium’s vision of helping people confidently ask questions and understand the world around them.

Our World in Data (ourworldindata.org)

Focus: Global development, economics, and social statistics. Our World in Data is a scientific online publication based at Oxford University that compiles data and research on the world’s largest problems – from poverty and disease to climate change and population trends. Completely free and open-access, it presents trustworthy statistics through interactive charts and articles that are easy to understand. Each topic page (e.g. education, health, environment) is written by experts and is continually updated with the latest research. The site’s educational value lies in its ability to show long-term trends and evidence in a clear way, helping readers of all ages make sense of complex global issues. All content is rigorously sourced and the project operates as a non-profit public good, so learners can confidently use it to expand their knowledge of the world.