Learning is a continuous process which starts right from the moment we breathe for the very first time though some might argue that it starts even before that when we are exposed to numerous factors affecting our physiology during our in utero life. Whenever it starts, it surely continues throughout our life till we breathe our last though some still might argue that learning continues even after that while we continue our search for perfection!
During the course of our life we radiate whatever we learn. This 'radiation' makes the basis of teaching which can either be passive if it involves just the way we behave or active if it involves a deliberate effort to train others. Imparting knowledge or education requires understanding human psychae and can be improved by systematically studying effective methods of educating others.