Hi, my name is Aaron Liu and I'm a family physician in Philadelphia, PA. I joined this forum to interact with interesting people and to learn about physics. For example, I am interested in maintaining my car, and I became interested in how internal combustion engines work. I am trying to learn how to drive my car and how to maintain the fuel delivery system so that the car's life can be prolonged. I like chemistry. I especially enjoy improving my intuitive understanding of Newtonian mechanics--concepts like angular motion, acceleration, force, and energy conservation--so that I can understand physical phenomena better and understand how things like machines and industrial processes work. I am also interested in forms of energy--such as light, sound, and heat--and their behavior. I am interested in electromagnetism and in DC circuits, but I'm more interested in appreciating them than doing heavy mental lifting to understand them deeply. I'd like to know things like how a transformer works. I'd like to know why the windshield of my car contains annoying reflections that decrease visibility, and how its manufacture produced that result. Things like that. I like it when people can explain things by simple concepts, analogies, and equations that I can add to my working knowledge... so I can understand the everyday. I'm sure I'll ask more questions than I will give answers.