Do you flip a coin or what? Looking at course descriptions, I found everything ranging from EE (especially the bio applications) to geophysics to be interesting. I understand that between physics and engineering, the core courses will be very similar for the first year but still, I was wondering if one has enough time to sample enough of everything to be able to commit to a major by the time they have to declare one? If not, how can one go about to get a feel of every thing they're interested in? Sit in the said lectures or tutorial sessions? Start reading a few books on the more specialised subjects once one has done the core-mathematics sequence, intro bio, intro chem, classical mechanics, waves and E&M?