Polar - he has a bit of a difficult time relaying information verbally, but he does understand how the molecules of a crystal grow, and can do an okay job of explaining it. (He's got a hard time remember to include all the information. He tends to launch into things as if you already knew what he was talking about.)
That's ok! Not many 3rd graders *are* able to relay this type of information easily verbally

Judges are kind and understand that, and they see a *lot* of projects so they can sniff out which kid is clueless (and there probably will be one or two who really didn't do their projects). And judges *love* to see enthusiasm - which is what they will see if he launches off into things... he's a 3rd grader. *TOTALLY* expected

Good luck to your ds!
polar