Survey Says!

by Matthew Luskey on February 5, 2015


In the first week of the term, Physics lecturer, Dr. Naresh Sen, poses a question to his PHYS 122 students.

A ball is thrown straight upward. At the top of its trajectory, its acceleration is.

A: zero

B: straight up

C: straight down

D: depends on the mass of the ball.

The answer, duh, is A. The quick histogram results of the clicker question show most of the students in PHYS 122 agree with me. I think of it this way: the ball stops moving at its apex just like that exquisite moment in late October 2002 when Kenny Lofton’s fly ball hung with zero acceleration in the night air before plummeting down into Darin Erstad’s mitt.


Turns out, my grasp of Physics, unlike my memory of the Angels’ World Series victory, is illusory. The correct answer is C, straight down. As Dr. Sen points out, I have confused the distinction between acceleration and velocity.

I’ll cut myself some slack for missing this one. Call it poetic license; my degrees are in English. When you say “double star astrometry,” I think Walt Whitman. But what about the other PHYS 122 students? Why do the majority of them miss this problem when they have much more recently studied gravity and acceleration in PHYS 121? Again, Dr. Sen explains: “In an Introduction to Physics course, one of the early and important learning objectives is to grasp the relationship and the distinctions between position, acceleration, and velocity (x,v and a).” Our prior assumptions about what these concepts mean can stymie us.

Herein lies one of the values of the clicker question:  it surfaces the extent to which one’s prior knowledge can help or hinder learning. As Susan Ambrose and her colleagues point out in How Learning Works, prior knowledge often hinders learning when it is “inactive, insufficient, inappropriate or inaccurate.” Basically, I have no business associating that World Series moment with the PHYS 122 question. Faulkner might call me out here: “Memory believes before knowing remembers.” Conversely, prior knowledge can help learning when it is “activated, sufficient, appropriate, and accurate.” (14)

Deftly and tactfully, Dr. Sen’s clicker question exposes these two conditions of learning. After posing the question, Dr. Sen asks his students to confer with others and to explain how they determined their answers. Those who grasp that gravity is always making the ball accelerate down are able to justify to others (the misinformed majority) the validity of C. Those like me who are operating under an inaccurate understanding of acceleration as velocity are much less convincing and clearly less able to justify our answer. Wheat and chaff are soon separated.

Rather than feeling shamed by my misunderstanding or defensive, I am invigorated. The use of the deceptively challenging clicker question and the subsequent interaction with my colleagues has activated my learning. As the Clicker Resource Guide prepared by the staff of the CU and Carl Weiman Science Education Initiative points out, “students often learn more from a clicker question they get wrong.” Because the conditions in which I answered the question were low-stakes and interactive, I am more receptive and engaged. I’m certainly much more apt to retain the correct answer and the explanation for it when the question resurfaces in an exam. “Fool me twice, shame on me!”

Nor is my misunderstanding a slight to the instructor of PHYS 121. (In my case, we have to travel back to the late 80s). Frankly, this failure to transfer learning or a dogged allegiance to a misconception happens all the time, and it prevents us from moving forward in our learning. As educators across the disciplines, we encounter this in myriad ways. In my writing courses, the hinder indicators are apparent when students ask me if they can use “I” in their personal narratives, or if they can start sentences with conjunctions. Answer: it depends on the rhetorical situation.

The research on clickers (or similar personal response systems) suggests that learning transfer and retention is more apt to occur when such devices are used to:

  • Integrate and advance learning
  • Provoke debate and discussion
  • Foster peer teaching and learning
  • Expose the process of how students understand or misunderstand

They are less effective when simply used to:

  • Track and test students
  • Ask true/ false questions


In effect, clicker questions can make otherwise passive learning experiences dynamic, and they make the often messy learning process visible. And that in turn can make the learning more likely to stick and to transfer.

A number of Cal Poly instructors use clickers (or similar peer response systems) in large and small courses. A recent CTLT Brown Bag session, featuring Dr. Sen (Physics) and Dr. Goschke (Biological Sciences), showcased examples of how rich clicker questions are used innovatively in both large and small classes. To view the slides from their talk, please visit the CTLT Clicker page. You’ll also find useful links to additional resources, including an excellent video, from the University of British Columbia’s Carl Wieman Science Education Initiative and the University of Colorado.

In the spirit of the clicker, let me end by asking a few questions meant to stimulate discussion. Please answer in the comments section below this blog. Let’s discuss.

  • How and when do you use clickers in your classroom? When are they most effective?
  • If you have resisted the use of clickers, what are your reasons?
  • If you are interested in testing out clickers, how can the CTLT support your efforts?

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