Sixteen is a tough age. First, ask yourself if his grades are on par with his abilities? If you don't know- ask his teachers. If he is not performing up to school standards, his abilities or well enough to help achieve his reasonable goals, such as college entrance- then you may wish to all sit down and discuss the matter with the school guidance counselor.
However, if he is achieving as much as he can- then perhaps the normal growth spurt of 16 is making him fatigued and he is requiring more sleep which could be considered laziness.
Consider asking about a mentor program within your school or community, as well.
Louise Sattler, NCSP
Nationally Certified School Psychologist
It looks like you are taking the first significant step - you are paying attention! Unfortunately, a parent taking notice of his child's schoolwork is often something that falls by the wayside during the teen years. So, you're making progress simply by being attentive to his study habits.
Let him know that you notice his lack of motivation, and ask him if there's anything you can do to help. It's important to actively engage him with him to promote his learning.
Try helping him set goals. Chances are, he wishes he had better study habits too. While I don't know your son personally, my opinion is that nobody wants to do poorly - whether it be academically or otherwise. Help him come up with some short and long-term goals that he wants to achieve academically.
Maybe he doesn't want to score below a C- on his next science test. That is something he can and will achieve, if he sets his mind to it. Urge him to talk to the teacher, in order to get help and seek tips that will help him to study for the next exam. The teacher should be able to help him come up with some study strategies - flash cards, practice tests,sitting up front, etc. that will help to boost his knowledge of the subject.
He should also make some longer term goals, like passing science, improving his GPA. By taking baby steps by meeting his short-term goals, he'll be better fit to achieve his bigger goals as well.
Below, I'm including a link to one of my favorite articles on the subject: "The 7 Habits of Highly Successful Teens." It may provide some helpful insight!
Great advise given already. I would like to add some thoughts to the 7 Habits of Highly Successful Teens. The concept of people are responsible for their own happiness is probably very hard for a teenager to accept. Rebellion and blaming other is far to common, but introducing this concept may put enough resonable doubt in their mind to, at least, not focus on what others have done to them. In rare cases, they may even consider the fact that they may be able to change something.
Beginning with the end in mind: teens rarely have a good understanding of true long-term goals such as career and retirement, so avoid these for the most part. Long term goal for a teenager is probably graduation or maybe even college. Most cannot see past Friday night. Make sure you focus partly on small accomplishments so that they can see the results of their actions. Teens, especially, want proof. They've heard the speeches, but get frustrated easily because of lack of patience. Seeing results makes it easier to believe.
Win-Win. If you can teach a teenager the benefit of giving up some of their time to get something in return, then you have laid the foundation for teaching them the value of studying and work.
Also, don't be afraid to use this tactic as well. Give up some of your time to do something that your teenager wants. While you are driving him to a friends house, ask him practice questions from his homework. Ask you teen to test your knowledge of his study questions. He may be suprised at how much you know or don't know, but he probably won't realize that he is learning while he is testing you. It could be a fun experience for both of you and he may also be motivated to show you that he can do better than you. You may also learn something too. Win-Win.