I, too, have judged many science fairs, helped science fair participants,
served on science fair committees, and was for two years Chairman of the
Greater Vancouver Regional Science Fair Committee. My overall impressions
are pretty nearly identical to Donald's, not favorable at all, I'm afraid.
Excellence in science at university and success afterward don't seem to
be highly correlated with science fair participation in my experience. I
must reluctantly conclude that as science teaching or science promoting
activities, science fairs are not worth the effort expended on them.