Perhaps it’s worth distinguishing between two types of “I don’t know”:
I don’t know because I haven’t put any thought into it. (This is the type of “I don’t know” that teachers rightly discourage.)
I don’t know because I have considered several hypotheses, and none of them explain my observations. (For example, my mental model of heat conduction predicts that the close side of the plate should be hotter, not the far side, so that explanation fails.)
Perhaps teachers should encourage students to replace “I don’t know” with “my mental model predicts A, but I observe B”, which communicates that the student is thinking correctly about the problem.
Perhaps it’s worth distinguishing between two types of “I don’t know”:
I don’t know because I haven’t put any thought into it. (This is the type of “I don’t know” that teachers rightly discourage.)
I don’t know because I have considered several hypotheses, and none of them explain my observations. (For example, my mental model of heat conduction predicts that the close side of the plate should be hotter, not the far side, so that explanation fails.)
Perhaps teachers should encourage students to replace “I don’t know” with “my mental model predicts A, but I observe B”, which communicates that the student is thinking correctly about the problem.