The brainchild of former North Carolina State University professor Marshall Brain, this site uses various media, including podcasts and videos, to explain how things work. It is essentially a popular science site but contains a great deal of high quality educational content and has now expanded to cover non-science subjects (see for example How Nepotism Works). Searching is made easier by a clear interface in which categories with their various subdivisions are simply displayed: the Engineering Videos page, for example, features categories such as Robotics, Buildings and Structures, Materials Science. The site’s videos and podcasts are supplemented by a number of blogs.