This is hard to really know for certain, but out of the 5640 visitors in November, about 93 came from sites identified with the IP subdomain address '.k12', representing 75 distinct 'schools'. Visitors from the .EDU domain contribute about 1200 visitors, but these are mostly from colleges and universities.
I get about 3-5 requests per month from K12 students asking for science fair topic ideas, and about 2-3 questions per month from individuals who identify themselves as elementary school students.
Most of the questions by children seem to be along the lines of 'How far away is the Sun?' or 'Is there life on Mars?', or 'What is it like being an astronomer?'.