How are gamma rays turned into electric power via solar cells and power stations? What chemical is used in dry cleaning? What are the physics behind a returning boomerang? When fielding these or similar questions, consult Marshall Brain's HowStuffWorks. This one site explains nearly everything you can imagine. It specializes in the mechanical, but it also tackles social concepts, cultural events, business jargon and so on. The site uses simple language in logical, easy to follow descriptions. Most explanations are spread over several screens--this means a lot of clicking, but each segment of an explanation contains links to further information and tangent topics. Though the site is dense, it is difficult to get lost entirely.
The site is fully searchable so one can get right to what one wants. A typical search will result in many different approaches to a topic (theory, history, related items/ideas, derivative inventions, etc.). Almost all definition screens contain photographs, graphics, or animated diagrams to demonstrate how things work. Definitions are often sprinkled with jokes and anecdotes to make the reading entertaining, but not so many that the authority of the explanation suffers.
The homepage is often revised to remain current and to provide links to the newest or most popular queries. It also features "Top Tens" in the left margin so one can see what people recently have been curious about. If you are a regular visitor, there is a link to the newest articles at the bottom of the main page. There are also discussion forums, gadget of the day, animation of the day, factory tours, and an animated tour of the Web site that highlights the site's features for the newcomer.
The site's drawbacks are not egregious. Due to its vast amount of information and the creator's desire to present something for everyone, the pages are very busy. Each page of a description contains a central text box about the subject at hand. This is surrounded on all sides by menus, advertisements, additional links, means by which to "tell a friend," and so on. The font--also due to crowding of a lot of material on each page--is sometimes small and can tire the eyes.
Wonderful pluses are that the site is largely translatable using Babblefish.com. Most of the definitions have stated authors and the material is very up-to-date. The site offers a free newsletter to anyone who asks for it and it also sells print books filled with the most often discussed and most popular topics.
University of Arizona