On the teaching channel I watched the video, Using Art to Help Students Express Social Issues, that showed a high school art classroom. The instructor talked about ideas of  physical wall and physical barriers. Then she moved to more conceptual abstract ideas of barriers. I really liked how the teacher was able to move from the physical  thing to the conceptual, which is often hard to accomplish.
Students used the artist reference, El Anatsui, in order to create a multi media piece students joined together three pieces of  recycled plexiglass.  
Students first researched a conceptual barrier, i.e. glass ceiling. Then they presented it to the class, so students were researchers and instructors, helping to co construct a body of knowledge. 
The teacher also utilizes peer critique for students to discuss each others work. She also talks about how her class is a lab, in which there is an important internet based element. She also says that keeping her website up to date is really important for struggling students or English Language Learners. 

Yamashita, Kathy. (2014). "Walls & Barriers: Using Art to Express Social Issues."

The Teaching Channel.  Retrieved from https://www.teachingchannel.org/videos/art-and-express-social-issues.