Do I think or listen - physics talks I am just a student, still I have already listened to a few talks on physics. In my study program everyone has to give a talk of about 45 minutes what he did in his about 1-2 month reach project during the 'holidays'.
I often sit in those talks an also can keep up for the first 15 minutes. Then it happens very often that there is something that I don't understand at first glance. I think to myself, is this really right or might there be an error. At this moment of time comes my problem:
Do I give this problem a minute and if I don't come to a clue, ask a question, but if it got clear I was left behind by the talk or might have missed important details. So is it maybe better to skip it and continue.
I have never been on a real physics conference, but I guess there the same problem occours. It would be nice to have some experienced answers to this 'Do I think or listen' - problem.
 A: Given the homework tag I'm going to give the teachers answer: you should have read over the material before coming to the lecture so that you know roughly what to expect. That will let you concentrate on the tricky parts and the places where the presenter want to emphasize something that may not be obvious.
The alternative is to use the lecture as preparation for the reading which you will do later.
Either way, the lecture should not be a solitary exposure to the material, so you don't have to pick one or the other.

At conferences the problem is a bit different, and you simple have to try to do both. Or makes note of where to get the followup reading.
Alas, I usually make note of more followup reading than I will actually get to.
A: Few short answers


*

*It's always, always, always, ... better to think by yourself than being coach potato during some other's talk.

*Most of the people present their results, after they're already published. You can alway take the reference, and take an eye on the paper when you have time.

*If people are not presenting some published result, then I would say it's fair enough to stop them as soon as you no more understand something.

*Usually, you will notice in the audience if you start annoying everyone with your questions. After all, the speaker is not only here to answer your questions, (s)he's here to deliver a message. It's also her/his role to postpone some questions for later, private discussion.


As I like to think, a seminar (as well as lecture, but most of the student apparently disagree about that) should be a dance for two. If you feel a talk was not interesting, it's partly your fault. 
Also, only dictators are talking for hours without any audience reaction... 
