Lewis Branscomb discusses how he decided to major in physics.

Branscomb:

I'll give you one other incident that happened when I was an undergraduate student. World War II was going on. I had left prep school early. They had an early admission scheme then, and I was an undergraduate at Duke, with majors in these two subjects, spending most of my time as editor of the student newspaper trying to choose between journalism and political science, and science and math. And Professor Paul Gross — who was chairman of the chemistry department, and subsequently acting chancellor of the university, and a neighbor and a family friend — grabbed me one day, and took me on an illegal tour of all of the secret war research going on at Duke. They were working at the time on automatic homing torpedoes and such things — including a fascinating project that had to train bomber gunners shooting at fighter planes with graphite bullets, in which you could actually shoot an aluminum airplane and the bullet would break up and leave a mark and not injure the airplane. The problem was, the fighter planes were nearly as fast as the bullets. Gross took me through this war work, and when he was all done, he said, "Look, any undergraduate that does graduate school level mathematics owes it to himself and his country to do science." That was a pivotal experience in making a decision on which way to go. From a biographical point of view, it's pertinent that that decision was made with reference to the importance and utility of the area of work, and not solely on purely intellectual grounds. But I made the decision largely because I occasionally made a B in physics. I never made anything less than an A in political science. Political science seemed trivial to me — the academic study of political science, not the reality — and I found physics and mathematics more challenging.