My advise, keep yourself busy. Bring some food with you, and make sure you get a bit of time to stretch. I've done the 11 hours day before (although I didn't have a break at all), and by the end of it, it's fairly tiring. The more friends to keep you company in those classes, the better. Avoid being a loner on these long days.
I've had 4 hour chem labs with no breaks.
When a lab is scheduled for 3 hours (or more), it won't be necessarily that long. You can leave a lab whenever you want after you get your name marked off (if you want to be recorded for attendance). You may find that labs never actually run for the entire scheduled time, with the extra time arranged for students to discuss any issues with the lab instructors. Regardless though, if you want a short break, you won't be stopped from leaving the lab for a drink or some food. Just as long as you don't bring it into the lab. They don't care when you leave so have a break at your own discretion. Make sure you tell your lab partner though so they know where you have gone.
Thanks for the advice, I'll try to do that =) Bringing food is a good idea, I always forget though.
I am working part time, but the reason for having a day like that is the timetabling for my classes was really bad this semester. In order to be able to go to all my lectures and tutorials I had to re-enrol in one of my accounting classes as a night student. So I have the pleasure of being at uni until 9pm, oh joy =P Like I said, it's doable, just tiring. Atleast I only live 15minutes from campus.
