As an elementary student 20-some years ago, I assumed that my teachers had all the answers. And as a new teacher I thought that I should have all the answers. The idea that students might ask me a question that I didn't have the answer to was scary. Wasn't I supposed to be the holder of all knowledge for my students? How was I going to become the master of all of that information? And once I learned all of that content, how would I even remember it all in order to teach it??
I have since learned otherwise. I have learned that it is okay to say "I don't know" to my students.
Students are always surprised the first time that they hear me respond, "I don't know," to a question. They expect their teachers to be the experts in the room, but my job as a teacher is not to be the answer-giver. My job is to teach my students how to learn, and every time that I say "I don't know" and we pull out an iPad, or a book, or we call a neighboring classroom to gather information, I am teaching my students how to be learners.
It is important, however, to take action in the moment that you say, "I don't know." I don't like to use "Parking Lots" or to write the question on a post-it note for later because often, then, the note gets forgotten or is no longer relevant by the time you get back to it. As soon as the "unanswerable" question comes up, I capitalize on that teaching moment--this is the time to model for your students how to be a learner! In my classroom this might involve modeling how to use search terms in Google, or guide words in the dictionary, or how to navigate the index in the back of an informational book, or how to determine reliable resources on the web.
At the beginning of the year, I support students in using their resources to find the answers that they need. If an "I don't know" comes up during whole class discussion, then we look up the answers whole class; and if the "I don't know" comes up during independent work, I support the individual in looking up the answers. As the year progresses, though, students become more and more independent in finding answers to their own questions, and I see them take more control of their learning. My favorite moments are when a question arises during a whole class discussion, and rather than wait for me to even say anything, students are running to their iPads or Chromebooks to Google the answers and are shouting out their learning to the rest of the class, building on each other's responses, and confirming or denying their peers' reports. Watching my students become facilitators of their own learning is when I am certain that it is, in fact, okay to say, "I don't know."