Well, just ask one. Or, maybe note the popularity of the term "teacher burnout"; you don't suppose they get burned out due to too little time working and not enough stress, do you?
Do the math. For each 1-hour class that a teacher holds, just how much time should she be spending outside the classroom in support of that class? Start with the entire notion of "grading papers". Let's say the class has 25 students (hah!). And let's say they are all assigned to write a 500-word essay. How long does it take to grade a 500-word essay? Two minutes? Three minutes? Four minutes? Whatever you come up with, multiply by 25 students. Then decide just how often a teacher should be assigning 500-word essays -- and homework, pop quizzes, semester exams, basically anything and everything that doesn't consist of the kid sleeping in class. When you figure all this out, put down a number for an average amount of time a teacher should spend "grading papers" for each hour of class time.
Next, figure out how much time the teacher should be spending preparing for each hour of class time. Is she just supposed to walk into class that day and "wing it"? It'd be kinda nice if she at least read the appropriate pages of the textbook, so she knows as much as the students do. She also needs to prepare tests, quizzes, whatever. She needs to make up handouts and study guides. She needs to spend a lot of time standing in front of a copier. And she needs to have a comprehensive "lesson plan" laid out that follows a logical sequence so she knows how to stay on track and teach the class what the curriculum says must be taught in the time allotted.
Now, to be fair, if a teacher has two or more classes that are supposed to be the same, she can save a lot of time on preparation. Use the same tests, the same handouts, the same lesson plans, just make more copies. This is important, and teacher contracts often specify how many different "class preparations" a teacher can be expected to teach and under what conditions. There is also considerable benefit in being an experienced teacher, meaning you have all the handouts and tests from last year to work with -- although, ideally, you'll be changing the tests each year to minimize cheating.
Next, figure out how much time the teacher should be spending on "problem children". At the very least, she's going to have to attend a parent conference or two for each one. She'll probably also have to write some notes to parents or make telephone calls. She's probably going to have to prepare some paperwork and fill out forms to justify whatever remedial action is called for. And there's the oft-overlooked issue of problem parents, where the kid is doing just fine but the parents want to have meetings and "get involved" anyway.
Wanna toss in coffee breaks and trips to the bathroom? Well, forget it. If a teacher needs to go to the bathroom, it'd better be before school, during the 22-minute lunch, during her "planning time", or after school. And during the 22-minute lunch, she's also expected to share a single microwave with 30 other teachers, supervise her class eating their lunch, and -- oh, yes -- eat.
And, finally, note that everyone from administrators all the way up to Congress seems to feel that teachers have lots of time on their hands and are desperately in need of training, seminars, meetings, you name it. The school calendar year often has several "teacher plan days" included in the schedule, but are the teachers ever allowed to actually use these days for planning? Invariably, some administrator or another considers a plan day his opportunity for calling a half-day meeting to discuss the curriculum or some such. And these meetings are invariably mandatory, because if the teachers were allowed to decide for themselves if they needed to be there nobody would show up. These meetings are almost without exception a complete waste of the teachers' time and are held only to justify some administrator's existence. Yet those administrators get irate if the teacher opts to grade papers while listening to some desk jockey drone on about how they could be teaching better.
On top of all this, many parents actually expect teachers to spend time before school, after school, or whenever to tutor their little darlings one-on-one. And if they don't, they get all incensed and try to get their kid moved to another class or get the teacher fired for incompetence.
OK, so what kind of numbers did you come up with? Remember, the question was how much time the teacher should be spending on each class, not how much they actually do. I'll give you some hints: In Japan, teachers spend less than half of their workdays teaching class; each teacher has her own office with a desk and spends more than half the workday in preparation for classes. Here in our own country, college professors typically teach 12 hours of classes per week on a full-time basis.
Is the light starting to dawn yet? Yes, in this country teachers are typically expected to teach five classes in a six-class day. The sixth hour is their "planning time", which apparently is supposed to mean that somewhere around 22 seconds per student is a reasonable amount of time to grade papers and prepare lessons. Totally inadequate, of course; in fact, the hour allotted during school is always used to get things done that must be done at school -- using the computer, running the copier, meeting with administrators, etc., etc., and it's often not enough time just for these tasks. Any and all tasks that can be taken home are taken home, where the teacher then spends many long hours grading papers on her "own time".
Not surprisingly, corners start to get cut; some of these teachers have the gall and audacity to want to spend time in the evenings with their families. Teachers learn to have students grade their own papers in class, which sometimes can be a useful teaching method but more often is simply to get the job done. Teachers also learn to allow students time in class to do assignments that really could be done as homework; the kids love it because it saves them time, and it allows the teacher to do some paperwork in class as well. Teachers learn to show films in class, and how to grade papers in the dark. Teachers who do this sort of thing are commended for their experience and efficiency.
But the most insidious result of this shortage of prep time is that the classes are not very intensive or demanding; since the teacher lacks the time to put together a really challenging and insightful lesson day after day, more often than not the class time is spent on little else than going over the reading assignment of the night before. And, of course, the teacher assigns less and less work in order to save herself the time required to grade it. The classes become less and less rigorous, and the students develop an attitude that their time is being wasted.
Our politicians ramble on year after year about class sizes, and class sizes are important, to be sure. But nobody talks about allotting teachers the time needed to do a good job. If those politicians really wanted to improve education in this country, they'd be working to get that 5-out-of-6 workday schedule changed to 4-out-of-6. And while such an improvement would obviously cost money, it wouldn't cost as much as reducing class size. To reduce class size, you have to build more school buildings and hire more teachers; to reduce teacher workloads to four classes per day only requires hiring more teachers.
Ask a teacher: would they rather have their five classes/day reduced
from 30 students each to 24 students each, or would they rather teach four
classes/day of 30 students each? Either way, the number of students
they face per day is reduced from 150 to 120, but the latter method saves
having to build more classrooms. And which change would do more toward
improving the education of our children? I submit that only one method
increases the amount of time each teacher has to prepare excellent lessons.