The words are accompanied by moving original illustrations and background audio, but perhaps the most useful elements are the interactive images. (t3.com)
In fact, the only useful elements found in bone are calcium and phosphorus. (professorshouse.com)
The privately funded Space Studies Institute, which he ran in Princeton, built working models of «mass drivers», electromagnetic launchers for putting payloads into lunar orbit, and commissioned investigations into the most efficient chemical reactions for extracting oxygen and other useful elements from the Moon. (newscientist.com)