Wide Angle Wednesday: Distortion

My photography classes are held in the UT Conference Center close to the University of Tennessee campus, and I shot this before going into class this evening.  When planning my entry, I had hoped for the other side of the building, because as you look down that side of the building you can see the  Sunsphere at Knoxville's World's Fair Park in the distance, but there was construction going on and the sidewalk was closed on that side.   

This is my entry for Mr. Hobbs' Wide Angle Wednesday challenge 'distortion'.  This is shot using an 18mm (27mm equivalent), and my instructor tells me that using this lens on my crop factor camera gives worse distortion than if used on a full frame. He explained, but I didn't get, the science behind this assertion, so I'll just take his word for it.

I didn't realize until just now that next week's subject is "leading lines', perhaps I should have saved this one for that one!  Oh well...