After I received Ph.D. in Physics at the University of Oregon, I have worked in Columbia University for more than 16 years as a research scientist. My research was in condensed matter physics/physical chemistry/chemical physics using scanning tunneling microscopy. I have taught Math and Physics to junior high and high school students for many years while I am in Columbia. I love teaching students and helping them better understand concepts confused clearly. I am happy to see that those studen...