Good suggestions given so far.
1) Talk with the teacher, counselor and ast principle. If necessary, ask to meet with the special ed/needs people as well..not classifying your son as special needs, but if the kids in the class are being mean and bullying, there are special needs there..bullies need lots of help or else things will get worse for everyone.
2) The science club is a great idea, if the school has one.
3) Check with any local science organizations, see if they have any group meetings for kids or any programs.
4) Get your son involved in Kensedo, Tae Kwan Do, or some form of Karate. This is an incredible sport for several reasons: it develops cross body functionallity which is crucial for effective and efficient body use and brain development. If you son is already brainy, the coordination and physical skill levels may not be as fully developed. Martial arts sports are the few that develop physcial control, mental confidence and control, respect, and self confidence. When your son knows what he can do physicaly, and not to say that beating someone to a pulp with little effort is a good thing, but when he knows how to control his body and just what he is capable of, his fear of bullies will diminish, his confidence will increase, and his comfort level with being a smart boy in a world that values "sport heroes" over intelligence will improve. He will realize he doesn't need to belong or rely on the children who are mean for his reaffirmation and value. He will have it all internally, which will insulate him from the cruelties children often demonstrate. And, when he has the confidence level, his patience and understanding with people who are not as quick intellectually and more reliant on physical strenght will improve, and he will be more comfortable in his own skin and intelligence. This is what we have found with our sons. Good luck.