Formative assessment probes are used not only to uncover the ideas students bring to their learning, they can also be used to reveal teachers’ common misconceptions. Consider a process widely used in inquiry science—developing hypotheses. Perhaps you require your students to develop a hypothesis before engaging in the process of inquiry. If so, how well do you (and your students) really understand the meaning and use of a hypothesis? Before reading further, think how you would respond to the probe “Is It a Hypothesis?” (Keeley et al. 2008; Figure 1). Which of the statements A–N describe a hypothesis? Jot down your answers and think about your conception of what a hypothesis is (and isn’t).