You may want to ask how science is handled at the school. At DD7's school science is one of their "specials" along with PE, library, music, art, and computer class. They have it once every 6 days with a dedicated science teacher who teaches students from K-5. Her approach has been hands on activities for the children which seems to help bridge some of the gap.

If your son's school has a similar set-up, it could help to talk to the science teacher about his strengths and what type of differentiation could be done.