How I Use It
In my experience, middle school students want to talk about tough and controversial topics. Researching these topics, however, is very tricky business for young students (and, let's be honest, a lot of adults too). ProCon lays out both sides of an issue with facts and research to support both sides. This is an excellent tool to work on argumentative essays.
I generally have students begin their research at ProCon.org. With advanced classes, or older students, I will often allow them to select an issue they want to discuss. Often,I will allow current events to dictate our research topic (Presidential elections, mass shooting, drug addiction, etc.) In their essays/presentations/speeches, students need to acknowledge the opposing side of the debate. After students become familiar with both sides of the debate, and write a short summary for each side, ProCon becomes a springboard into independent research.
ProCon can serve several purposes in the classroom. For myself, it has become a go-to resource when controversial topics pop up. I prefer to avoid situations where I might express my own opinions in the classroom (even when I'm right) and ProCon.org lets me give my students both sides. It has really helped to shut down outrageous arguments from students when things like welfare or gun control come up. More importantly, it encourages proper and healthy debate. ProCon makes it very difficult for students to throw a debate off the rails with wild manipulation of facts (or the absence of facts) and focuses the class on the true issues.
All in all, ProCon.org is a great tool for research and argumentation, but it is also a wonderful resource for teachable moments.