For Bohr, it was no question at all: "In 1903, I passed the A-levels at Gammelholm Latin and Upper Secondary School and began studying physics at the University of Copenhagen." (Later, Bohr also studied at Cambridge and Manchester).
Literature interested me [...] as much as sociology and the sciences in general. However, during those busy years [as a home school teacher in order to be able to finance studies], I tried to gradually find out where my real talent was, and so I finally turned to mathematical subjects and physics. My solitary course of study was, of course, full of difficulties. The scientific education I had received at high school was already very incomplete, and so I tried to fill in the existing gaps in my own way, i. e. with the help of books that coincidence threw into my hands. This method was not very effective, but it had the advantage that I got used to working independently and that I also obtained certain knowledge that was very useful to me later.
Einstein's plans (at the age of 16): "If I am lucky enough to pass my exams, I want to go to Zurich. I want to study mathematics and physics there for four years. Then I would like to become a teacher in those fields of natural science, choosing their theoretical part. The following reasons lead me to this plan: First of all, my inclination towards abstract and mathematical thinking and my lack of imagination and practical skills. [...] Moreover, scientific activity has a certain independence which I like very much."
After reading Weyl's "Space-Time Matter", the future mathematics professor said: "Then you are already spoiled for mathematics anyway." "So it was nothing with the study of mathematics. A disappointed consultation with my father led to the conclusion that I could also try studying mathematical physics."
Helmholtz was unable to study physics for financial reasons, but felt that he was a "born physicist". He studied medicine at the Friedrich Wilhelm Institute (the so-called Pépinière) in Berlin, where he committed to serve eight years as a military doctor after completing his studies. Due to his scientific achievements, three of these years of service were waived.
