"...What evidence is there for any of this? How about the twisted look on a student’s face when the challenge of learning is put before them." This comes from a blog post I'm working on. My question is, should I end the second sentence with a question mark or a period? It's a rhetorical question, so I think I tend to prefer the period, but I want to know what the accepted standard is.
I don't know what the accepted standard is but I would use a question mark in the second sentence as well.
It depends on what you second sentence is trying to say. If you are trying to respond to the first question with a question or an uncertain suggestion, then you would use a question mark. If you are simply making a statement, you would use a period. However, in this context, it seems like the question is the most natural.
I think the answer is in what you said: you think of it as a question. Questions end with question marks; it's that simple. If you thought of it instead as an answer to the former question, it would not be a question and a full stop would be the correct punctuation mark.
Question mark, yes. With the "how about", it's phrased as a question. To eliminate the question mark, remove the question phrasing: "...What evidence is there for any of this? The twisted look on a student’s face when the challenge of learning is put before them." "...What evidence is there for any of this? One piece of evidence is the twisted look on a student’s face when the challenge of learning is put before them." "...What evidence is there for any of this? Well, let's consider the twisted look on a student’s face when the challenge of learning is put before them." "...How can we prove this? One piece of evidence is the twisted look on a student’s face when the challenge of learning is put before them." Edited to add: The "how about" is also rather informal and slang like and a slightly angry-sounding challenge. So I'd eliminate it anyway.
