Puppy Nipping

Question
I have a five month old shitzu/bichon mix puppy.  We are having problems with him nipping.  When he is playing he gets very aggressive and trys biting us.  Not to hurt us intentionally...but it does hurt.  I have tried saying ouch in a loud voice and ignoring him but it does not seem to work. He just seems to get more aggressive.  When he does this I put him in his kennel..but it is not stopping.  My young grand daughter came to stay with us for a short time and he kept trying to nip at her.  any suggestions as to how we can get him to stop this behavior?

Answer
Use a water bottle and tell him no loud and firm-that usually works

it will also help to enroll him in obedience classes as he is about the right age for that,and a trainer will go through the steps with you on how to correct any problems he has no