Mathematics, Science, Social Studies, English & Language Arts. Current K-12 education standards for all of these disciplines highlight the need to support arguments with evidence. 

There are a variety of frameworks that can be used to help students form strong arguments. We like the Claim-Evidence-Reasoning (CER) framework. This is not the only scaffolding tool out there. Please feel free to share your thoughts on others that you may use or wish you could use.

For the informal educators in the group, while you may not ask visitors to use a particular framework like this in discussions, I bet you still appreciate a well-supported answer from a student. If you are able, you may even want to ask teachers who are planning a visit whether they use such a framework with their students and work claim-evidence-reasoning language into your programming for those classes.

Trevor Register's January 13, 2015 Time-Variant Teaching blog is a nice starting point.

That blog, and other resources, refer to an Audi commercial that is commonly used to practice identifying claims and evidence and to develop reasoning. A colleague who is a teacher of 6th grade scientists has also used two songs from Disney movies for CER practice: That's How She Knows from Enchanted and Under the Sea from The Little Mermaid. 

Here is a formative assessment probe that asks Is it a Claim? And a formative assessment probe that asks Is it Evidence?

This web site has a student tutorial (and teacher's version) on writing arguments. Mouse over the Argumentation Tutorial tab to select which version you want to view.

Many CER resources refer to the work of Katherine McNeill. If you want to dive deep: I have seen some interesting discussions about whether McNeill and Krajcik conflate the practices of explanation and argument. This is one site where you can investigate that discussion. It refers to a 2011 Osborne and Patterson paper from Science Education that provides even more depth. A pdf of that article is provided below along with a related article (Argue and Explain) from December 2015 Science Scope.