Educational Theory Underlying Astronomy Clicker Questions & Peer Instruction

Tim Slater, CAPER Center for Astronomy & Physics Education Research,

As teachers, we make countless decisions about our classrooms every day. Some of them are obvious: “Am I going to talk about planets before stars today, or the other way around?” Others decisions are so subtle, they might go unnoticed: “Am I going to carefully grade every aspect of this assignment, like spelling and grammar, or am I just going to skim to see if this student has acquired the general idea?” With so many decisions to be made every day, you might think we’d be exhausted before we ever talked to a single student. And, we would, if it were not for the underlying philosophies about teaching and theories about learning that we carry with us to help us make these decisions. All too often, these philosophies and theories are completely unexamined, tacit if you will. Most importantly, if you want to improve your teaching effectiveness, understanding which philosophies and theories of learning you have adopted will allow you to make improvements in your students’ learning. Let’s consider some of the more prevalent theories and practices in teaching astronomy and see if you can gain some insight into how you are making decisions about your classroom.

Two Contrasting Philosophies about Teaching Astronomy

POSITIVISM. Undoubtedly, the dominant philosophy driving most of teaching is one based in positivism. In brief, and with sincere apologies to philosophers who have spent lifetimes eloquently describing the aspects of this philosophical position, positivism is based on a notion that we only learn what we have been told or directly experienced. An astronomy teacher who devises instruction based on a positivist philosophy of teaching expends considerable effort on delivering precisely articulated lectures with cleverly illustrated graphics and illustrations. They believe that students do not know anything about the Universe before entering their classroom and it is their task to clearly describe the nature and mechanics of the world to self-motivated students who should be intrinsically eager to experience their lecture. They disappointingly view disinterested students as unfortunately individuals who are choosing to miss a rare opportunity to learn. Most importantly, most positivist teachers believe that a lecturers’ enthusiasm is probably the most important aspect to gaining and keeping student attention so they can learn. Among college and university professors, this is clearly the most widely adopted philosophy of teaching. At secondary levels, this is somewhat less prevalent, but still dominant. In this instance, the theoretical position, which is really a philosophical one, is that students learn astronomy by attentively listening to precisely delivered astronomy lectures and the practice consistent with this view is to provide accurate, professor-centered instruction where the teacher, or by proxy the teacher’s assigned readings, is the sole source of information and learning in the course. Students’ are assigned homework or in class activities designed to practice reciting or applying the teacher-delivered procedures—tests are more of the same.

CONSTRUCTIVISM. Perhaps the most influential teaching philosophy driving innovation and reformation in astronomy teaching is that of constructivism. Constructivism is grounded in the notion that students enter your classroom already holding pre-existing ideas about the way the world works. In this context, students enter your classroom already knowing why it is hotter in the summer than in the winter, why the leaves change color in autumn, and why rain falls from clouds. Many of the ideas and explanations students hold were constructed with considerable mental effort and students deeply own and are committed to holding on to their ideas. The problem for the astronomy teacher is that some of the student-created explanations about how the Universe works are scientifically accurate, whereas many others are completely wrong.

In the late 1960’s, noted educator David Ausubel (1968) was well known for saying that “the task of the teacher is to determine what the student already knows and teach them accordingly.” In response, much of the astronomy education research since that time has focused on devising strategies to measure the range and domain of students’ misconceptions in astronomy. The number of tests for measuring the knowledge and conceptual knowledge in astronomy is a lot and these surveys and tests have evolved considerably over the years. Currently, the best landscape survey we know of is probably the TOAST Test Of Astronomy STandards (see Slater, Slater & Bailey, 2011). The driving force behind the effortful construction of such surveys is to carefully determine what students initially think they know about astronomy as they come into the classroom so that the constructivist teacher can teach the students accordingly. Constructivist astronomy teachers pay careful attention to the results of these surveys and tests.

A constructivist teacher recognizes that their students already hold ideas about astronomy, some correct, some incorrect, and many partially correct. As a result they spend considerable energy questioning students to find out what they think. In real-time response to their questions, constructivist teachers continuously query their students about examples and counter examples and provide students with metacognitive feedback about their own evolving ideas. Most constructivist teachers realize that students don’t simply move from the wrong idea to the correct idea, but that there is long, convoluted journey with multiple pathways in leading students to more complete and scientifically accurate ideas. Teachers who hold a constructivist teaching philosophy tend to be more open to trying different teaching innovations as compared to their positivist philosophy holding colleagues. In this context, the theory is that the teacher’s job is to move students from naïve understanding and misconceptions to scientifically accurate understanding of astronomy. The practice aligned with this philosophical position is that teachers are not only dispensers of knowledge, but rather serve as coaches and guides for students who are responsible for the learning. Homework or in-class activities then take the form of aligning student thinking with scientific thinking, often making use of collaborative groups (Adams & Slater, 2002).

moving-from-teacher-centered-to-learner-centered-versionAThese are not the only two teaching philosophies, but rather represent two opposite ends of a philosophical continuum. Perhaps, when thinking about how these perspectives are manifested in the classroom, this continuum is better described as a teacher-centered to learner-centered classroom continuum. In the teacher-centered classroom, the teacher is the primary source of information and ideas, and is characterized by the teacher doing most of the talking. In contrast, in the learner-centered classroom, the students are doing most of the talking, debating, and articulating of ideas—often talking to each other rather than to the teacher.

Theories of Learning Focusing on the Teacher

If you understand that there is a continuum of different teaching philosophies, you probably wouldn’t be surprised that there are a number of theories of learning as well. There are far too many theories of learning to describe in this short space, but a few are worth describing because an awareness of learning theories help us to better describe why we do what we do in our astronomy teaching.

For teachers who are inclined toward a positivist philosophy of teaching, briefly described above, their most likely corresponding theory of learning is that of TABULA RASA. As eloquently described by Vosniadou (1998), Tabula Rasa can be literally translated as “blank slate.” Teachers who subscribe to a Tabula Rasa theory of learning view their students as essentially having a blank slate in their heads about astronomy. They view their job as an astronomy teacher is to write precise information in students’ empty minds. In general, they do not believe that students hold a pre-existing understanding about the size and shape of the Universe, the physical processes that cause stars to shine, or about how planetary surfaces change. More important to our discussion, when these instructors do agree that their students have misconceptions about astronomy, they strongly believe that students need to be told more clearly, if not more loudly, the correct ideas and that these correct ideas will simply erase and over-write any old or incorrect ideas. This is highly characteristic of a teacher-centered approach to teaching, particularly those who teachers who spend most of their time at the front of the room lecturing to students who are taking notes to memorize later.

At the same time, teachers who hold a Tabula Rasa theory of learning implicitly believe that students will most value and record the information told to them by the instructor with the highest credentials. When students fail to learn from an instructor who holds a Tabula Rasa view of learning, either it is the students fault for not fully being attentive during class. If the teacher receives blame for insufficient learning, the most common intervention is to ensure that the failing teacher fully understands the science underlying what they are trying to teach, often by requiring them to sit in on some graduate-level astronomy course to refresh and improve their understanding of astronomy at the most complex levels.

Astronomy Clicker Questions: Teacher-Centered Instructional Strategy. Learning theories adopted driving teacher-centered classrooms do not always look like a lecture-based classroom. A classroom setting that looks very different, but still driven by a theory of learning focused on the teacher being the expert who moves information from themselves to the student, is a classroom based on notions of SOCRATIC DIALOGUE. Socratic dialogue is a learning theory based on the idea that if students are simply asked the correct questions in the correct sequence that the student themselves will come to know an idea. Although lecture is a teaching strategy on could adopt and use no others, a more common strategy for intellectually engaging students with questions to think about and debate is Think-Pair-Share, also known as Clicker Questions and described in detail elsewhere (see, for example, Slater, 2008).

THINK-PAIR-SHARE is an approach where the teacher presents an idea in a traditional lecture format and then asks students to stop taking notes and answer a question about the ideas they were just presented. Questions posed by the teacher to the students can either be simple recall (e.g., which planet has the highest surface temperature?) or can be questions of application (e.g., at which phase of the moon will a solar eclipse occur?). Less often, but still quite effective at improving students’ achievement, teachers can pose questions encouraging students to encounter a widely known misconception (e.g., how often does the Moon’s appearance change?).

What makes this approach different than simply interjecting questions to the entire group of students in a lecture is that the teacher directs this process in three distinct steps: (i) As an opening step, the teacher poses the question to students who must personally and privately commit to an answer without speaking to anyone. Traditionally, this is done after some lecturing has occurred. (ii) Next, the teacher asks students to vote on the question’s answer. There are two important reasons for this second step. The first reason is that students need to be held accountable for devising an answer to the question; if the students do not give a meaningful attempt to answer the question to the teacher, then the students haven’t actually engaged intellectually with the idea being taught. The second reason is that the teacher too needs to understand the extent to which students understand the topic so that they can decide if more lecture needs to occur. If most of the students have the correct answer, then the teacher can move on with the lecture. On the other hand, if most of the students have an incorrect answer, then the teacher needs to re-teach the idea, perhaps in a different way with different illustrations, examples or analogies.

As a brief aside, this think-pair-share approach of asking students to answer and then provide their answer to the teacher requires the teacher to have an infrastructure or system by which to get students’ answers. Experienced teachers know that if they ask students to share their answers in front of the rest of the class, rarely will more than one or two students volunteer an answer freely. It is possible to randomly call out student names and ask them to provide an answer—one such strategy is to write student names on pieces of paper or popsicle craft sticks and then randomly draw a students’ name—but this astronomy teaching practice can be risky because some students are simply unable to speak confidently in front of the rest of their classmates. Instead, a common practice is to give students a sheet of paper or a small chalk or re-useable white board on which they can write their answers in big letters and then simultaneously all hold up their answers for the teacher to see and evaluate. This approach to having students hold up their solutions on a piece of paper or erasable board is generally known as WHITE BOARDING. More recently, teachers have started using cell phone voting systems where students can text-message their answers to the teacher or a computer system where the frequency of various answers can be rapidly tabulated for the teacher. Instead of clicking their cell phone key pads, some teachers ask students to purchase electronic personal response systems that allow them to send their answers as “votes” to the teacher’s computer. These often look like handheld television remote controls, and are called “clickers.” Because of the rapidly growing abundance of these clickers, sometimes this think-pair-share teaching strategy is more widely known specifically as using ASTRONOMY CLICKER QUESTIONS (Waller & Slater, 2011).

Going back to the steps in this think-pair-share approach, there is a third step that can often be used in this teaching strategy. It is this third step that is often the most valuable part of this teaching strategy. In the event that 40-70% of the students have the correct answer, then the teacher asks students to collaborate with another student, in a pair of two students, to discuss their answers and their rationale for why they answered the way they did. After students have had a few moments to share their answers and rationale and contemplate their partner’s answers, students are asked to vote again.  What generally occurs is that a much larger number of students, if not all, have come to the correct answer without further teacher intervention.

One might be concerned that students will “teach one another” incorrect ideas without the teacher present to monitor and correct scientific inaccuracies. Perhaps surprisingly, this intervention on the part of the teacher is rarely needed. Students generally teach each other correctly because the scientifically accurate ideas are generally easier to explain and defend than the inaccurate ideas. More importantly, students who have just recently come to understand the new ideas are better able to know which aspects of a concept are most confusing and are much better positioned to help other new learners come to know an idea than a teacher who struggled with learning the idea for the first time themselves years or even decades before. Students who are talking to other students of similar age and similar cultural backgrounds are able to use a more natural student language with analogies and metaphors that the teacher might be unable to devise to help students learn. In other words, students are well positioned to explain ideas to other students in ways that are most rapidly comprehensible.  Ongoing discussion among faculty talking about how to best use this strategy can be found over at the Turn to Your Neighbor Blog.

This CLICKER QUESTION strategy exploits and leverages this situation and has been shown to dramatically improve student learning. The reason this three-step approach is known as THINK-PAIR-SHARE is because students THINK first by themselves about a question, the PAIR collaboratively with another student to share their thinking, and finally they SHARE their answers and rationale with each other and the teacher.

Countless astronomy students are using astronomy clicker questions with varying degrees of success.  By and large, our experience is that most people who have used them, continue to use them course after course.  At the same time, talented teachers are creating their own astronomy clicker questions based on Peer Instruction.  A great 60-min YouTube video on this is available by Derek Bruff. Many astronomy clicker questions are archived and freely available at the Astronomy Faculty Lounge which can be accessed through the FACULTY LOUNGE portal at the CAPER Center for Astronomy & Physics Education Research website at (Slater & Slater, 2013).


Adams, J., & Slater, T. (2002). Learning through Sharing: Supplementing the Astronomy Lecture with Collaborative-Learning Group Activities. Journal of College Science Teaching, 31(6), 384-87.

Ausubel, D. P., Novak, J. D., & Hanesian, H. (1968). Educational psychology: A cognitive view.

Crouch, C. H., & Mazur, E. (2001). Peer instruction: Ten years of experience and results. American Journal of Physics, 69, 970.

Mazur, E., & Hilborn, R. C. (1997). Peer instruction: A user’s manual. Physics Today, 50, 68.

Mintzes, J. J. (2006). Handbook of college science teaching. National Science Teachers Assn. – featuring articles by Eric Mazur and Tim Slater

Slater, S.J., Slater, T.F. & Bailey, J.M. (2011). Discipline-Based Science Education Research: A Scientists’ Guide, 2011. W.H. Freeman Publishing and Company, New York. ISBN 1429265868.

Slater, T.F. (2008). First Steps Toward Increasing Student Engagement During Lecture. The Physics Teacher, 46(8), 554-555.

Slater, T.F. & Zeilik, M. (2003). Insights Into the Universe: Effective Ways to Teach Astronomy, American Association of Physics Teachers Press: College Park, MD (160 pages). ISBN: 1-931024-04-9

Vosniadou, S., & Ioannides, C. (1998). From conceptual development to science education: A psychological point of view. International Journal of Science Education, 20(10), 1213-1230.

Waller, W.H. & Slater, T.F. (2011) Improving Introductory Astronomy Education in American Colleges and Universities: A Review of Recent Progress. Journal of Geoscience Education, 59, 176-183.


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