ebeth,

In the middle school my kids have gone to, out 7th grade science is good, but not that tough - I really believe an advanced 8 or 9 yr old could do it. I'd be surprised if my sons take more than a few lines of cryptic notes, and really that's only if it's required. If you decide to proceed with the acceleration-- remember, you can reverse it if it isn't working.

It's such a shame that time will be spent traveling to/from the other school, especially in today's age of technology. What does he miss during the traveling? I wonder if you could visit the class with your son and see what it's like (and if it's worth the trouble, stigma, etc.)

Everywhere I look there are virtual labs available free online, free podcasts of science info, tons and tons of stuff out there that no classroom teacher has time to access even a fraction of it. Yesterday I looked at the NASA website--lots of stuff. Our state Dept of Health has a lot, too. EPA website is loaded. Cogito.org. Videos--Discovery channel, planet earth BBC series, our library has many. Science experiment books. I guess what I'm trying to say is, isn't there a way to give him time, opportunity and a little proctoring to do some advanced independent work? So many things to explore, so little time.
Mind you, I am rarely one who would shy away from an offered acceleration. Maybe your middle school and later your high school are pleasant, civilized environments...But! I just walked through our high school and got caught in the hall when the bell rang. It was Crazy. Large people, some scary and weird, and so many kids. I actually thought about my DS10 and how I couldn't imagine him going there for math class (which is what I thought about this year). Too frightening for me & I'm Old.