I once explained arrays and frontbuffers/backbuffers to a 9 year old. I can't say that he did anything useful with the knowledge, though he wasn't put to sleep by it and went away knowing a little more on how graphics are done.
There's quite a bit of a gap between an understanding sufficient to follow someone else's explanation and an understanding sufficient to build something (including learning a rigid syntax understandable to a machine in order to express the concepts).
