Science & Nature
1439 sites
Subcategories:
- Astronomy & Space (396)
- Chemistry (8)
- Earth Sciences (26)
- Biology (79)
- Physics (30)
- Mathematics (59)
- Weather & Climate (104)
- Amateur Radio (682)
- Electronics (47)
https://www.qsl.net/9m6aac/old/aacmem.htm
The Hillview Gardens Amateur Radio Club (9M6AAC), based in Keningau, Sabah, Malaysia, maintains this membership directory listing callsigns and contact details for its globally dispersed ham radio members. The roster spans operators from dozens of countries, reflecting the club's mission of promoting worldwide friendships through amateur radio.
http://users.netonecom.net/~swordman/Radio/unun.htm
Doug's page details the hands-on construction and testing of an impedance-matching transformer (Unun) for connecting a 350-foot long-wire antenna to a shortwave receiver. Complete with photos of the wound toroid core, schematic references, and bandscanning results comparing performance with and without the transformer, it's a practical reference for anyone building receiving antenna accessories.
https://gutenberg.org/cache/epub/11587/pg11587-images.html
A digitized 1922 educational text by Charles Lathrop Pack, President of the American Tree Association, covering all aspects of forestry from how trees grow to national forest policy and the dangers of fire and disease. Hosted on Project Gutenberg, this freely available ebook spans 18 chapters and includes period photographs of forests, rangers, and fire damage, making it a fascinating historical resource on early American conservation thought.
http://stargazing.net/david/constel/skymapindex.html
David Haworth's stargazing site offers a comprehensive index of printable sky maps organized by month, time, and observing location, with five detail levels ranging from basic star fields to full constellation boundaries. Each map links to more detailed constellation charts, making this a practical reference for amateur astronomers heading out for a night of naked-eye or telescopic observing.
http://rocketroberts.com/astro/astrophot.htm
Joe Roberts shares a remarkable personal archive of amateur astrophotography spanning from 1974 to 2013, featuring backyard telescope images of deep-sky objects, planets, comets, and lunar phenomena. The site includes technical articles, a tour of his personal observatory, and a gallery of stunning images that rival professional observatory photography from decades past.
http://science-workshop.com/
Science Workshop appears to be a science-oriented site, though its content is extremely minimal with only a single image visible at crawl time. The domain name suggests a focus on science education or hands-on scientific topics, but without further content the site's exact subject remains uncertain.
https://cut-the-knot.org/
Created by Alexander Bogomolny starting in 1996, Cut the Knot is a massive encyclopedic collection of interactive mathematics covering geometry, algebra, probability, puzzles, proofs, and much more, built over decades until his passing in 2018. With thousands of pages, interactive Java applets, Olympiad problems, and articles spanning all levels of math, it stands as one of the most beloved and comprehensive math resources ever built on the early web.
http://dfma.org/
The Durham FM Association (DFMA) is an amateur radio club based in Durham, North Carolina, serving members across the Research Triangle Area with repeaters, monthly meetings, and public service activities. The site covers club events, repeater information, newsletters, ARES/AUXCOMM support, and Field Day activities, making it a central hub for local ham radio enthusiasts.
http://worldclimate.com/
WorldClimate.com is a comprehensive database of historical weather averages for over 85,000 locations worldwide, offering rainfall, temperature, and precipitation records spanning decades. Travelers, researchers, and curious minds can look up climate normals for cities from Bangkok to Lima, making it a handy reference for trip planning, relocation decisions, or general weather curiosity.
https://ancient-skies.org/
Ancient-Skies is a collaborative scientific knowledgebase dedicated to documenting how human cultures across history have understood and represented the night sky. The project, launched around the International Year of Astronomy 2009, aims to gather and verify information from primary sources, making cultural astronomy accessible to both the general public and researchers worldwide.