"Students are advised that getting the right answer is NOT the purpose of a science fair project.
Although there's lots of fun science stuff to peruse here, you'll find the meat of the matter in the Soup to Nuts Handbook written by Janice Van Cleve, author of more than forty books on science and science fairs.
Science Buddies is a non-profit organization encouraging students to "improve their science skills" and "consider additional study or careers in science.
This excellent guide from David Morano of Mankato State University in Minnesota, walks you through the all steps involved in an experimental science project.
From astronomy to zoology, All Science Fair Projects is a searchable database of 500 science fair ideas for all levels (elementary, middle and high school.
Each year there's another batch of science fair pleas in my mailbox. "Help! My daughter (or son) needs a science fair project. Can you suggest one?" Each year, my answer is always the same: no. I make a point of not doing my own kids' schoolwork -- so don