Science & Technology

How Stuff Works http://www.howstuffworks.com/ This searchable website is a “leading source for clear, reliable explanations of how everything around us actually works”.
Mind Matters http://www.sciam.com/askexpert_directory.cfm Website run by Scientific American. Database of frequently asked science and technology questions. Features a short list of currently popular questions at top of page.
Public Library of Science http://www.plos.org “The Public Library of Science (PLoS) is a nonprofit organization of scientists and physicians committed to making the world's scientific and medical literature a public resource”.

Science Search Engines