Put your Boolean and other searching skills to practice with the challenges below.
Start with The Invisible Web or Deep Web, Part 3 -- Two search challenges. The second part, PowerReporting, is designed for students of journalism,not high school students, but you can learn a lot about locating difficult-to-find information on the Internet. Notice how a good searcher is flexible and determined, willing to try a number of different approaches.
Continue with Part 4 -- The Invisible Web or Deep Web, Chasing Down a Low-Flying Aircraft. Hint: When the information you want is probably in the deep web, search for the database, not for the information - in other words, use the word "database" at Google along with terms you think might lead you to the correct database.