Materials Research - Discussion rather than written

My Year 13 inquiry group are at the point in their design development work where they are writing the analysis notes with their design work.
I put a support document together for them and shared it on the class Google Plus Community so they could make a start on these notes and we did an exercise all together where we looked at an existing stage set design and analysed it together.
We then ned to start thinking about what materials would be the best to use for the designs they have produced. This is normally quite a dry activity of finding information about various materials, writing out tables and comparing them.
I decided we could incorporate our talking practice into it this time. I collected some information about a variety of likely materials and put it onto a presentation.

The students then got themselves into pairs and chose one material each from the presentation. They then had to tell the other person why they had chosen that material based on it's fitness for purpose and sustainability. They then had to tell their partner why their chosen material was not a good idea so it involved them listening to each other.