Two key challenges in science instruction are identifying the naïve conceptions and misconceptions students hold and getting past those misconceptions. To illustrate, let me begin with a story.
Early in my teaching career, I would sometimes go into my school at night when it was empty and I could get work done. My 5-year-old daughter would often come with me and play while I worked. She and I would always walk down the long corridor from my classroom, passing through a set of double doors that were usually open, to the cafeteria to get a snack from the machine (a time-honored practice known to parents worldwide as bribery). One night we were there later than usual, and these doors were closed. My daughter went running ahead of me, curls bouncing and—with no signs of slowing—ran smack into the closed doors, bouncing off them and landing on her bottom.
I was dumbfounded. After picking her up, I asked her why she hadn't slowed down. She said she thought the doors would open by themselves like she'd seen other doors do when you get close to them. When I asked her what she would do next time she saw a set of closed doors, she replied that I should run ahead and make sure the doors were open for her. As a parent, this wasn't exactly the response I was looking for, but such is the mind of a 5-year-old.
My point in sharing this story is that students come to us with perceptions about how their world operates, perceptions shaped by their experiences. In my daughter's case, experiences gathered at the hospital, grocery store, and local mall had molded her perception.
Our students' perceptions, and the experiences feeding them, are as diverse as their backgrounds. The difficulty comes when students' experiences have produced misconceptions that conflict with concepts we're trying to teach. If we aren't aware of these misconceptions, we may set students up to run into the proverbial closed door.
The gateway to effectively uncovering and changing students' misconceptions is predictive questioning. This strategy, used in conjunction with strategic discourse, is a powerful tool (Chin, 2007). Learning, especially the type of inquiry-based learning encouraged in science classrooms, is a socially mediated endeavor. Inquiry loses its punch without strategic discourse, whether that discourse is with the teacher or among students (Abell & Lederman, 2010). To get a sense of how using predictive questions to uncover misconceptions works, let's examine a lesson I recently taught my 12th grade astronomy students.
Busting Myths About Gravity
I hoped this lesson would lead students to an understanding of the evidence for dark matter in space. I wanted them to understand that the amount of gravity in our galaxy isn't enough to account for the high orbital velocities of the stars near the galaxy's edge. Even stranger, stars moving at those high velocities should be escaping the galaxy's collective gravity and flying off into space—yet they stay in their orbits. This implies that something besides the visible mass we can detect in our galaxy is holding the galaxy together.
Before students could understand this "missing mass" dilemma, they had to have a foundational understanding of gravity. The lesson started with helping them grasp the law of universal gravitation,
Figure
which tells us that the force of gravity (F) is affected by two things: mass (m) and proximity (r). The force of gravity gets stronger if objects have more mass and if objects are closer together; the converse of each statement is also true.
Students needed to understand that gravity acts as a tether holding objects together, that objects can overcome their gravitational tether when they achieve high enough velocities, and that the gravitational effects we see within galaxies can't be accounted for by looking solely at the mass from luminous matter (matter that can be detected on the electromagnetic spectrum). I used carefully planned questions to lead them toward these understandings.
I began by asking each student to predict the orbital velocities of something familiar to them—the planets in our solar system (What happens to the orbital velocity of the planets as they get farther and farther from the sun?). I also asked them to explain their reasoning, providing a graphical as well as verbal explanation; they would later observe data on these orbits and revise their explanations as necessary.
These questions were folded into a protocol that I call the predict–explain–observe–revise cycle—modified from White and Gunstone's (1992) predict–observe–explain strategy. Students predict the outcome of a potentially discrepant event; explain their reasoning (including graphically if they are looking at the relationship between variables); observe the actual phenomenon or data; and engage in strategic discourse in small groups—which leads them to revise their explanations based on the evidence.
As I expected, most students predicted that orbital velocities would increase as planets got farther from the sun, giving explanations similar to that shown in Figure 1. In physics class, they had learned about linear velocity, which explains that when an object spins around, the outside part of that object spins faster than the inner part. I suspected I would have to reveal—and break down—students' misconceptions so they would realize that this principle doesn't apply to the individual orbits of planets and stars.
Figure 1. Sample Student Work in First Part of Lesson on Dark Matter
Next, students collected and observed and graphed actual data on the orbital velocity of our planets. Finally, in small groups they evaluated this data, talked together about what might explain it, and revised their explanations for the orbital velocities.
Once students' misconceptions about gravity and objects spinning in space were uncovered, each group was able to use its discussion and consideration of the new data to come to more accurate explanations. Students took responsibility for mediating the discussions. Occasionally, when a group wasn't quite there yet, I'd drop in and engage one group member in this kind of questioning:
T<EMPH TYPE="5">eacher: I heard you say something interesting about the planets and stars. Would you be willing to share it with me?S<EMPH TYPE="5">tudent: Sure. I was positive that the planets would get faster the farther they got from the sun, but they didn't.T<EMPH TYPE="5">eacher: Why did you think that?S<EMPH TYPE="5">tudent: Because we learned in physics that a ball at the end of a string spins faster and faster the longer the string is.T<EMPH TYPE="5">eacher: Let me see if I understand what you're saying. Let's think of a DVD spinning around inside a DVD player. You're saying that the part of the DVD closest to the center spins slower than the part of the DVD that's near the edge?S<EMPH TYPE="5">tudent: Yeah. But that's not what the planets did. They got slower as they got farther away from the sun.T<EMPH TYPE="5">eacher: What could explain that?S<EMPH TYPE="5">tudent: I don't know.T<EMPH TYPE="5">eacher: What formula do we have that explains how matter behaves gravitationally?S<EMPH TYPE="5">tudent: The law of universal gravitation. Oh! The planets get farther and farther away from the sun, so gravity decreases.T<EMPH TYPE="5">eacher: Why isn't that the same as the DVD?S<EMPH TYPE="5">tudent: Because the DVD is one solid thing, but the planets are all separate.
At no point did I need to give away answers: I only needed to ask predictive questions, provide data for students to analyze, and ask students to expand on their thinking by talking within their groups.
Getting to Powerful Questions
Predictive questioning with strategic discourse is especially powerful when students hold firm misconceptions. Every year in my physics class, I have students who swear that shooting a marble straight up in the air before it lands on a runway will cause it to go the farthest down that runway. It isn't until the marble hits them on the head, and they answer a few pointed questions, that they realize that shooting an object straight up only gives it height, not distance. If I simply told them this would happen, it wouldn't have nearly the impact.
Any well-structured, inquiry-based lesson is rooted in careful questioning. Like Carnac the Magnificent on the old Johnny Carson show, effective teachers can predict the most generative questions to ask—as well as the answers students are most likely to give—not because they're mind readers, but because they have thought deeply enough about the lesson to envisage what those questions and answers will be (Di Teodoro, Donders, Kemp-Davidson, Robertson, & Schuyler, 2011). Savvy teachers prepare ahead of time questions that will do three things: elicit prior knowledge, uncover student misconceptions, and move students toward their conceptual goal.
Notice I didn't say you should give the answers—only that you should predict what the answers will be. It can be incredibly tempting to move this process along by giving students the answers when you see them struggling. But it's a mistake to do so in an attempt to spare them discomfort or because you don't think you have enough time.
Write down your most important questions and carry the list around with you as you check in with student groups. This way, you'll be sure to ask each important question to each group. Occasionally, these well-crafted questions still won't be enough to elicit the understanding you are targeting. It's important to dig deeply for understanding because we as teachers are so familiar with the content that we may lose track of how difficult it is for students to grasp the content. This phenomenon, called the expert blind spot (Fisher & Frey, 2010), can be avoided with savvy prediction about where students might get stuck.
When a learner does get stuck, it's essential to have a follow-up question or cue that will scaffold that student's conceptual awareness and point toward the targeted content. Consider this dialogue:
T<EMPH TYPE="5">eacher: What's a nocturnal animal?S<EMPH TYPE="5">tudent: An animal that stays awake all night.T<EMPH TYPE="5">eacher: Tell me more about that. Does a nocturnal animal have special characteristics?S<EMPH TYPE="5">tudent: Well, it doesn't sleep a lot. [misconception]T<EMPH TYPE="5">eacher: I'm thinking of those pictures we saw of the great horned owl and the slow loris in the daytime and at night. Does your answer still work? (Fisher & Frey, 2010, p. 15).
This teacher wanted to uncover a student's misconception that nocturnal animals sleep very little. So she drew attention to photos the student had seen that showed such creatures sleeping in the daytime. Had the teacher stopped at her first question, she never would've uncovered the underlying misconception. And had she not had her follow-up prompt prepared, she would've missed a perfect opportunity to push the student to examine his or her own thinking rather than having that thinking corrected by the teacher.
It's powerful to reframe questions to use the word you. Imagine that after a student sees a discrepant event (such as a just-launched marble falling straight back down), you ask, "Why did that happen?" On the surface this seems like a legitimate question. However, it sets a student up for trying to explain the right answer and will likely reveal little about the mental models that learner holds. Instead, ask "Why do you think that happened?" or "What do you think will happen?" These questions encourage reflection and require the student to make his or her covert thinking visible—even if it isn't right.
Your probing could stop here. But remember, you're asking these questions because you've predicted that students harbor misconceptions that might warp the lens through which they view the content. It's good to ask a further question—like "Why do you think that?"—that enables you to uncover the underpinnings of students' thinking.
The reason to keep probing is like the reason to have a house professionally inspected before buying it. The house might look fine on the outside, but on closer inspection you discover the foundation is riddled with termites. The earlier you know, the sooner you can do something about it.
Using the Cycle in Layers
The predict–explain–observe–revise cycle can be used in layers. For instance, in the first part of my dark-matter lesson, I used the cycle with a concept that was familiar to the students. After this cycle was completed and students' misconceptions had been addressed, we began a second cycle with content that wasn't familiar. This second cycle took advantage of the conceptual work done in the first cycle to "feed forward" students' learning.
In this second cycle, I asked students to predict the orbital velocities of stars beyond our solar system, stars located farther and farther away from the galactic center. Every student predicted that these stars' velocities would slow down with increasing distance from the center, explaining their predictions with phrases like, "the more distance between the center of the galaxy and the stars, the less pull gravity has, so stars will orbit slower." They were amazed when I shared the actual data, which shows that orbital velocities increase and level out with distance. I also pointed out that stars orbiting at that velocity should be flying out of their orbits—yet they remain fixed.
As they discussed this data, student groups lit up with explanations. My questioning guided students back to their understanding of gravity, mass, and proximity, and their effects on orbital speeds. Eventually, each group decided there must be some sort of "missing mass" within the galaxies that holds them together and causes the orbital velocities of the outermost stars to remain high—but that this mass wasn't showing up on the electromagnetic spectrum. This led students to request additional information about the existence of dark matter and how it can be detected. For instance, one student revised her explanation like this:
We decided there has to be more gravity to hold onto [the stars]. But we didn't know where it was coming from because we can't see anything else. A group member said it's dark matter, but we don't have any evidence (yet!) that it is.
Integral Tools
Strategic discourse and predictive questioning are integral to learning through inquiry in science classrooms. Used together, these tools tease out students' misconceptions, create opportunities for meaningful dialogue among students, facilitate higher levels of student engagement, and result in deeper learning.
