CSI: The Experience Web Adventures is a great web site that teaches students about forensics and then gives them virtual cases to work on and apply their knowledge. It is supported by the National Science Foundation and partners Fort Worth Museum of Science and History, American Federation of Forensic Sciences, CBS, and Rice University Center for Technology in Teaching and Learning. Some pretty big names!
There are three different cases for students to solve ranging from beginner to intermediate to advanced. Each case has the student learning new topics and concepts in order to solve the case. The cases are very well written and designed and I had fun trying them out.
The site also has a reference section for help with the cases, topics and characters and the "fun stuff" section has an educators guide with lessons and activities, family guide and more to make the experience even better.
This is a great site and experience for any science student. It is definitely appropriate for grades 9-12 and I think 7-8 could do very well too.