I think there are a couple of main reasons.
First, you do not have enough time in the school day to learn all the things you need to learn and to get all the practice you need in order to be sure that you are really learning the stuff.
Second, when you get to college, you get tons of homework. If you never have any homework in high school, you are unlikely to be ready for it in college. In that case, you're in deep trouble.
So, basically, like so much that adults tell you to do: "it's good for you."
BTW -- if you are going to say you don't need homework, make sure and spell your words right so you don't make us think you need more homework...
It really depends on who you ask. If you were to ask John Taylor Gatto, he would say that you are given homework so that the school can reach into your home life and take away your privacy there and be sure that any learning or development you take part in will be according to what the school wants.
If you ask most teachers they will say that they are hoping to reinforce things you learned in school or give you practice, so that when it comes time to test the skill you will be able to knock things out quickly without having to think too hard, etc.
If you ask some teachers, they might say they don't give much homework as they believe that your time at home (the tiny bit that many students have these days) is your own to do with what you will.
The comprehensive answer to this question might lie in the specific teaching philosophy of the teacher. Ideally, the concept of homework is to give a reinforcement of concepts taught in school. Think of it like this: You are in a classroom for 40 minutes. Once you leave, there might be moments when you reflect on what was taught to you or what you experienced from an academic point of view, but realistically speaking you are away from the specific content and its enhancement for 23 hours and 20 minutes. Homework allows some interim contact with content that might allow you to reflect, develop more questions, and help assist you so that difficult concepts become easier to manage. I have always felt that students who look at classes as "40 minute students" without giving some level of reflection outside of class bear more difficulty than those who are working both inside and outside of class.
Homework is given to reinforce what you learned at school. It is given as practice to help solidify the lesson in your memory. The more you complete a specific type of task, the better you will be at it. Have you ever heard of the expression practice makes perfect?
Homework is also an assessment tool for teachers. It helps them gauge where a student is in the learning process. If a student is utilizing faulty methods in completing a task the teacher will notice and hopefully help the student with remediating the error.
I'll just give you my personal reasons for assigning homework.
1. I teach English (literature and writing), and an obvious requirement of English class is reading. Students simply do not have enough time in class to reador for me to help them perfect their analytical and writing skills; so much of the reading must be done outside of the classroom. Admittedly, if most of my students chose to read on their own, I would not have to assign as much reading homework because reading is central to learning and analysis, and my students would already have a great deal of practice with it. Unfortunately, each year that I teach, the number of my students who choose to read as a hobby decreases.
2. I also assign homework because I want my students to practice skills that we have discussed in class. I do analyze all of my students' homework so that I know if they are learning or if they need help on specific aspects of a skill.
3. Finally, I assign homework because some of my students go to college and some go directly into the work force and for either path, most of my students will have some type of take-home work--whether it's homework in college or an employee having to bring home schematics or other job elements to study and perfect (my husband is in the Army, and he often has "homework" for his job). By teaching my students that learning is not confined to the classroom, I hope that they will be better prepared for whatever they choose to do after high school.
I do believe that some teachers assign "busy work" for homework, and I don't agree with teachers' not at least looking at their students' homework because that sends the message that there really was no point in a studentcompleting the work--how is he supposed to know if he is practicing whatever the skill is correctly if a teacher does not even look at his homework?
Homework is very important for numerous reasons. One of the most important reasons that teachers assign homework is to enforce what was learned that day. It is a fact that people can retain information for a longer period of time if the work is repetitive. In other words, you cannot simply hear something once and remember it. You need to hear it and study it many times for the knowledge to sink in.
Another very important reason that teachers assign homework is that it teaches responsibility. Homework teaches students that in order to receive good grades, there must be a considerable amount of time put into it. The reward is a great grade which makes you feel good about yourself.
Homework is kinda "dome" I guess, if you don't do it. You can't learn everything you need to in the time span of a class period. If you want a diploma to mean something, to enter college prepared, or to avoid becoming another uninformed American (of which there are plenty), you'll have to develop a work ethic on your own. It may not seem important now, but you'll realize why homework is an important part of your education later on.
There is many reasons, for example it is very easy to forget what you did. Homework reminds you of what you did and also improves you on that skill. Teacher can also imply a special homework that lets you experience what you will be learning in the future.
Being a student for quite a while now, I have pondered this myself. Mostly when I was younger and hated the thought of homework, but I digress. I believe why students receive homework even though they do even more work at school is, in most cases, for extra practice. For example, in math, you work on/go over problems in class, and then are usually given an assignment to further practice them at home and increase your understanding.
I understand why a little bit of homework is necessary, but there are so many things that could be better than spending hours on homework.
1. Getting exercise. The first thing that is substituted for homework time is exercise. When I was in primary school i used to spend hours each day after school playing soccer or footy or something like that. It barely happens anymore, and you can tell.
2. Work. As students, it's good to start saving money so that further studies can be pursued, so that you can help your parents and start off life on the front foot financially. But it's practically impossible to juggle homework and work at the same time.
3. There are other activities which are good to do as well - things like practicing musical instruments. These are very beneficial to students, and are believed to improve intelligence.
4. Hobbies. Every student needs a hobby, and if he/she doesn't have time to relax and do what they want to do, they lose interest in life. Trust me, I've experienced it myself.
Anyway, that's what I would like to say about homework.
There are several ways in which people learn some of these ways of learning require interaction with teachers at school, and perhaps also with other students in the class. Such types of learning is best imparted by many students assembling at a common place like a school.
Other ways of learning do not involve such interaction. In this type of learning students learn by practicing some of the things learnt at school. Students also learn through self study from books and other sources of information such as the Internet. This type of learning activities which can take place at home also, is best done as homework.
If students were required to do the homework activities also at school, they will need to spend much more time at school. Besides they will have reduced flexibility in the timing of doing such studies.
In education a concept or methodis taught at school by the teacher. Quite often a person is unable to have the level of practice necessary to help the person to gain a total understanding of the concept. Homework is like practice. It enables a person to demonstrate knowledge and practice techniques acquired at school through instruction.
Homework can also serve as an assessment tool. By checking student's homework teachers are able to determine if the studen has an understanding of the concept or if additional education is necessary.
The other reason comes from my students; "Teachers give kids homework to torture them."