When I was a schoolboy, my classmates called me "our emergency helper" because of my ability to assist them and explain things clearly. I have been teaching or tutoring during most part of my career, first tutoring job involved third and sixth graders who needed help with mathematics. Then I tutored freshman students, later I became a graduate student and taught the section of physics laboratories for science majors for three years. During my postdoctoral appointment at Los Alamos, I tutored ...