Card Sort Hacks

light blue cards in the midst of being organized on a table top

Along my teaching journey, I started to incorporate more inquiry and modeling activities into my classroom at the expense of practice problems “drilling” concepts. Based on student survey feedback, I learned my students missed these drilling activities. They were craving practice they needed to master and get comfortable with the content.

Their request for more practice is validated by educational research highlighted in the book Make It Stick: The Science of Successful Learning1. According to the book’s author, Peter Brown, “retrieval practice - recalling facts or concepts or events from memory - is a more effective learning strategy than review by rereading” and “makes for stronger learning and retention.” He also claims “the act of retrieving learning from memory has two profound benefits. One, it tells you what you know and don’t know, and therefore where to focus further study to improve the areas where you’re weak. Two, recalling what you have learned causes your brain to reconsolidate the memory, which strengthens its connections to what you already know and makes it easier for you to recall in the future.” I now try to strike a healthy balance between inquiry and retrieval practice for my students.

One retrieval practice technique I find beneficial is card-sorting. A card sort is when students group or match cards together by a common association (figure 1). Many teachers enjoy using them to practice content. ChemEd X bloggers like Ariel Serkin and Chad Husting have discussed using card sorts in their chemistry classrooms. Their blogs are worth checking out. Jamie Flint has graciously shared many of her card sorts at ChemEd conferences over the years as well. If you have not tried a card sort in class, it is worth a try!

Figure 1: Example Gas Law Card Sort (in the process of being sorted)


My favorite card sorts are what I call “Johnstone Triangle Card Sorts”. The expression “Johnstone Triangle Card Sort” is not a real thing; however, I think the title does a great job describing the card sorts I strive to create for my classroom. If you are not familiar with Johnstone’s Triangle2, it consists of three domains of representation in chemistry: macroscopic, sub-microscopic, and symbolic (figure 2). Johnstone’s Triangle helps students develop a deeper understanding of chemistry by representing concepts through the macroscopic, particulate, and symbolic representations. ChemEdX blogger Erica Posthuma has written about the benefits of Johnstone’s Triangle, if you would like to learn more. In “Johnstone Triangle Card Sorts,” students group macroscopic, particulate, and symbolic representations of the concept. I included my Gas Law Card Sort as an example (see Figure 1 and attachment). This card sort represents gas laws through descriptive, graphical, symbolic, mathematical, particulate-level, and macroscale representations of the concept. As students sort the random pile of cards, they are retrieving information and making connections between different representations of the concept (graphical, mathematical, particulate, etc.)

Figure 2: Johnstone's Triangle


Below are some of my favorite Card Sort Hacks I feel increase their effectiveness as a retrieval practice activity.


Card Sort Hacks

  1. Provide each student with their own copy to cut out and use at home. I have a class set of card sorts to use in class and then send students home with their own personal copy to study and practice with. Instead of re-reading their notes, the card sorts provide students with a better retrieval practice option to use at home. I have students color or number the backs of the cards so when they flip the cards over, they can check their answers. For example, all of the Boyle’s Law cards may have a “1” on the back while all of the Charles’ Law cards may have a “2” on the back (figure 3). Play around with your school's copy machine to see which settings are needed to ensure proper alignment. If you decide it is not worth the hassle, I have students quickly use a red marker to draw a line behind all the Boyle’s Law cards and a green marker to draw a line behind all the Charles’ Law cards before they cut out. Alternatively, you can provide students with two copies of the card sort; one to cut out and the other to use as a key. When I have math problems in the card sort, I put the answers on the back of the cards so students can self-check answers (figure 3).
  2. Scaffold the card sort. When I introduce a new card sort, I have students work in pairs to complete. I hear great peer-teaching while students work collaboratively. Eventually, students work individually to complete as their assessment will be taken individually.
  3. Have an in-class race to see who can sort the fastest. During a card sort race, I have students randomly mix their pile of cards. When I say “Go,” students sort the cards. When they are done, they get up and line up at the back of the room in the order they finish. This helps me determine the order of completion when I am distracted by checking answers. When they start lining up, I go around and check to see if their card sort is correct. If I see a card in the wrong spot, I pull it off to the side and stop checking. The student may then return to their card sort and make corrections. They rejoin the line when they are done. I continue to check the next fastest student’s card sort. If a student has everything correct, I call out their place, like “1st place.” I continue until I have awarded the top 5. I give those students small prizes while the rest return to their seats and check answers against a key or by flipping over their cards. Students reflect on what parts they struggled with so they can develop a strong study plan. This is a great way to mix things up and encourage students to study at home so they can improve for the next race.
  4. Once students master the sort, level it up. To make the card sort activity harder, I randomly pick one card from the envelope containing the card sort. I have students write down everything else they know is connected to the card on paper, much like a quiz. For example, if I randomly select the Boyle’s Law graph card, students write down the Boyle’s Law math equation, particulate model, variables, description of the relationship, sample math problem, and lab observation. This activity requires the students to remember all the associations from memory, without the aid of seeing all of the possible options. I encourage students to do this with their own copy of the card sort at home to help study.
  5. Revisit card sorts from previous units. Once the card sort is made, it is easy to pull out at any time for impromptu practice. Card sorts provide a quick way to practice old concepts and keep the information fresh. According to Make It Stick1, revisiting card sorts from previous units will provide students the benefits of spaced practice and interleaving.
  6. Organizing card sorts. I like to store card sorts in lettered envelopes. I include the printed key in the envelope with the cut-out cards. I give students a large manilla envelope to store all of their different card sorts in. Students can 3 hole punch the large manilla envelope to store in a binder.
  7. Finding homes for lost cards. Inevitably, a random card will be found on the floor at the end of the day. To help determine the lost card’s owner, I letter the cards of each of my sets by putting the letter “A” on all of one set and the letter “B” on all of the second set, etc. If I see a letter “A” on the stray card, I know which envelope to put it back in. I have students put their initials on the back of all their cards so I can return the card to them if I see their initials.

Figure 3: Matching numbers on the back of cards as well as the answer to the math problem.


Card sorts provide a great way for students to practice and make connections. It helps students get more comfortable with the concept so they are better able to apply the concept to new situations. Currently, I am working on a new titration card sort for my AP Chemistry class. Like many of my teaching inspirations, it is turning into a larger beast than expected! I will share it in another blog when done and classroom-tested.

What are your favorite card sort hacks? Do you have a favorite card sort to share? Share your ideas in the comments section by logging in or registering for your free ChemEd X account today!

Editor's Note: Check out a digital version of the Gas Laws Card Sort using GIFs in Melissa's March 2021 blog post, Supercharge Your Classroom with GIFs.


  1.  Brown, Peter C., Make It Stick: The Science of Successful Learning. Cambridge, Massachusetts: The Belknap Press of Harvard University Press, 2014.
  2. Johnstone, A.H. J. Comp. Assist. Learn. 1991, 7, 701-703
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