Most middle school students (and elementary for that matter) don't deal with a change of routine very well. A fire drill in the beginning of the day will totally set them off and they'll be acting like nutballs the rest of the day. Taking them to another location for class - whether it's the reference room, the theater, or a lab - can be a challenge. They tend to lose their cool, and what little common sense they may have had.
So it was with some trepediation that we planned for not one, but two, lab days as part of our microscope unit. Mrs. Eagle, Mrs. Robin and I knew we'd be in for it, but the kids needed the practice on the microscopes and the only way they're going to get it was to take them to the lab and do it.
Of course, we all threatened them with just about everything short of death if they screwed up and misbehaved.
Amazingly enough, my kids did really well. In fact, so well that there were times I was almost nervous, waiting for the other shoe to drop. It wasn't a shoe, but a beaker, that did get broken but that's pretty minor considering what it could have been. The microscopes were all lined up along the counter and the kids did really well considering the close quarters and didn't squabble or fuss too much.
And they actually had the paitence to try focusing before they started squalling for me to come help them.