In the past, I've reviewed content in my high school Spanish classes by revisiting lists created at the beginning of the year on big poster paper about different topics that we study during the course. My sophomores come to me with many years of Spanish study (they start in first grade in my district) and so the review at the beginning of the year often brings back memories of earlier classes and gets them thinking about what they've learned so far about Hispanic cultures, what they don't know, and what they want to learn. In June, when we pull out the posters to see what they've learned, they are impressed by how their knowledge has broadened and deepened.
This is usually a foolproof activity, except... when you've lost the big papers from the beginning of the year. Oops. So I had to come up with something different. There were six units in the course, so I created six Google documents that were available to everyone. I created QR codes that linked to the Google docs, and printed out each QR code on a piece of paper with the title of the unit on it. I divided the class into six groups. Each student used the free Scan app to scan the code with their iPad. They could then view and edit the document. I gave them about five minutes to generate ideas for the first topic (everyone in the group could add information at the same time) before they passed the QR code to the next group. I gave them a little less time to add information with every rotation.
I thought this process had some advantages over my original lesson plan. First of all, it's paperless, so there's no danger of losing valuable information by throwing it out. Secondly, these Google docs could be easily added to a shared folder where students could access them and add more information as needed. Finally, every student was also able to add ideas to the document, whereas in my traditional paper-based station there's generally just one "secretary." I think using documents edited by multiple users motivates students and maximizes their participation.
The only problem I ran into was that a couple of students were writing inappropriate things on the Google documents. When I saw that, I stopped instruction and reminded the whole class that such behavior was unacceptable and if it happened again I would have them stack the iPads on my desk where they would sit unused for the rest of the year. (I could threaten that because they are school-owned and not students' personal property; also, there was only about a week left of class at that time and none of my other lesson plans were iPad-dependent.) The class fell into line immediately and it didn't happen again. I didn't follow up with the offenders, but I could do so easily by checking the documents' revision history to see which user posted which comments.
Have you used QR codes in class? What's worked well for you?