Archive | October 27, 2014

Day 36: Plickers


College-Prep Physics and AP Physics C: Today we tried out Plickers. It’s a student response system that uses paper clickers (hence the name plickers?) and the camera on the teacher’s smartphone/tablet to record their responses. The picture above is screenshot from my smartphone’s app: You can see the histogram of responses (top-right) and the class list with responses (top-left) overlayed on the camera view which flashes students names as it recognizes their responses as you scan the room with your phone’s camera. Each student has a unique QR-code card that they hold in different orientations to indicate a vote of A, B, C, or D. So a camera scan of a code identifies the student and how they are voting.

The inspiration for using Plickers started with my Global Physics talk this past Saturday. During the discussion, I talked a bit about Preconceptions in Mechanics, and Andy posted a link to his blog post about cards vs clickers. I reread Andy’s post that afternoon, and decided to make low-tech response cards for my students to tape into the inside back-cover of their lab notebooks:


Shortly after I posted that picture to Twitter, I got a reply from Lisa:

which prompted me to check out Plickers.

The Good: It’s set up very well for peer-instruction type discussions. While I scan the room with my phone’s camera, I can project the Plickers website from my desktop computer and show/hide a real-time histogram of students answers, or show the class roster which displays a check mark next to students who have registered their answers.


You can ask questions on the fly, or create a deck of questions in advance (like the one above).

The Bad: You can’t add pictures to questions or import a PowerPoint slide deck. But you can easily switch back and forth between applications if you want to show the class histogram after voting. Or just put up windows side-by-side:



While Plickers lets you go back and review the response history of a question, including individual student responses, it cannot generate a student report showing a history of all questions for a particular student. This isn’t a feature I need or use, but it is a feature that traditional clicker systems have, so I figured I mention it.

Time is another consideration. While scanning cards with the phone is rather quick, it’s still quicker to go the low-tech route with colored index cards or the 4-sided card I was originally going to use. But I’ll say that the histogram is really powerful, both for me and the students. Sure, I could say “Most of the class is voting B” or “Looks like there’s a 50/50 split between B and C” but for students to actually see the histogram (and to see it again after a peer-instruction re-vote) carries more impact.

In the end, I think the good outweighs the bad. I’m having the kids tape their Plicker cards onto the inside back cover of their lab notebooks.


UPDATE 28 OCT 2014: We did a set of Peer Instruction-type questions in AP Physics C today. There were a few hiccups — the network dropped a few times (an issue on our end, not Plickers) and some kids kept mistakenly covering up part of the QR code with their hands. And it does seem to take several seconds longer than just using colored cards and doing a visual scan. BUT the histograms are cool and provide some motivation and interest.

And something interesting happened today. When I did the Peer Instruction “vote – discuss – revote” cycle, rather than gravitate toward the right answer, the class split about 50/50 between the right answer and a wrong one. Now what? Discuss and revote again?






(The correct answer is C.)