The penny determination algorithm

Dan Meyer writes, on his blog:

Something I enjoy about computational thinking (the focus of my position with Google) is that it asks you to explicitly verbalize processes that may only exist in your intuition, processes that are too obvious for words. Case in point: which of these is a US penny?

100% of my students would correctly select I. But if I asked them, “Why? How do you know?” and requested a “Penny Determination Algorithm,” the sort of thing you could give to an alien race to identify our one-cent currency, it would drive them crazy.

“I don’t know. It’s just … obvious.”

My particular students may not be ready for that conversation but it would be a good one.