World-renowned theoretical physicist Albert Einstein was interested in explaining the theory of Relativity to people who were not especially well-versed in higher mathematic concepts and theoretical physics. His solution to this was to write the ground-breaking work, "Relativity: The Special and General Theory." In the paper, Einstein lays out two contradictory principles: a principle of relativity and a principle of light. Einstein proposed that,...

Designed to help listeners recognize birds of Western North America by their songs and calls. Points out exactly what to listen for to tell one bird from another.