http://www.newton.dep.anl.gov/
Newton BBS maintains an 'Ask a Scientist' program, where K-12 students and teachers can pose questions to mathematicians and scientists and receive an answer geared to their level of understanding. There are also archives of questions asked during 1993, with questions ranging from 'how do refrigerators work?' and 'What is the difference between an aftershock and an earthquake?' The subjects covered include biology, physics, chemistry, astronomy, and computer science. Users who log in directly to the BBS can participate in online discussions with teachers, scientists, or entire classrooms.