A Nebraska middle-school teacher is using a type of interactive whiteboard called a DualBoard that encourages classroom participation. The DualBoard allows teachers to post a question on a screen using a laptop computer. Students then use electronic clickers to answer, receiving instant feedback when the answer is revealed on the screen. The system allows the teacher to know which students answer incorrectly but keeps that information private from peers. It requires that all students answer each question that is posed, and educators say it helps them quickly determine who is struggling.