My day job is now substitute teaching, but I've resisted writing about it until now mostly out of fear. I mean, since that pays (even if it is meager) and this blog does not, there is an incentive for me to not screw it up. But, I realize it is a rather appealing topic. So let me just talk generally about the difference between age groups.
First, each school and even grade has its own sort of social hierarchy. The district I'm at has elementary, middle and high schools, and regardless of the age groups, the oldest class at each is always somewhat collected, and it all goes out the window the second they switch to their new school.
The change is almost shocking to witness. Formerly quiet and composed fourth graders become shrill, excited kids again, similar to first graders, once they hit the middle school. The same thing happens on the switch from middle to high school, with a bunch of puberty-effected freshmen bouncing off the walls. I've had a variety of different classes at each age group, and it doesn't seem to matter who their actual teacher is.
There is also a big difference between fifth and sixth grade, and ninth and 10th grade. Fifth graders still mirror elementary school students in many ways - the majority are well-behaved and open to instruction, and if they are in trouble, it's normally more hijinks than serious. (i.e. Teasing a girl vs. skipping class.)
But once they've been in the school for a year, the attitude comes, and it's like a light switch on. Most of the sixth grade classes I've had have been incredibly bratty and resistant to do anything at all, and the same thing goes with 10th graders and history. By the time they hit seventh and 11th grade respectively, they've again calmed down and work more earnestly, and get more distracted with their own social circles and what not.
Still, the change is noticeable and stark and just plain odd to me, someone without a teaching degree or a ton of classroom experience. I don't think it's an issue of just getting a "bad" group of kids, more that this is how they seem to shake out as they progress. Fascinating, in a way.
Also, to counter a commonly held belief - Today's kids don't really seem any worse to me than how I acted when I passed through the same school system seven to 19 years ago. If anything, things have gotten better, as there are more extracurricular programs offered, and more work being done to either help or separate the kids who just don't want anything to do with school.
My main issue would be the lack of accountability with parents - the most common complaint I've heard from teachers is calling home to remedy a behavior problem, and instead being accused of the one causing the issue. Of course, all teachers aren't perfect or saints, but the vast majority of the ones I've encountered do have their students best interests at heart and are qualified. Most of them aren't going to lie about Johnny F. Poopoopants not handing in their Algebra homework.