Wednesday, April 13, 2011

Crazy for Conic Cards!

I just finished another one of my favorite units: Conic Sections! I used to hate them, but now I love them (and so do my students). And it is all thanks to Cindy Johnson for sharing her conic section cards at an NCTM conference a few years ago. Her cards did more than enhance my unit on conics, they completely revolutionized the way that I teach this particular topic! Students learn by identifying patterns, not laboring over tedious formulas. Learning conics has never been so fun and painless.

Here is the basic idea:  You have a bunch of decks of cards (hopefully, you have a student aide to copy, laminate, and cut them for you). Each deck contains 20 equation cards (5 for each conic), 20 information cards, and 20 graph cards.  They are corresponding so that students can match each equation to its information and graph.  There are also four title cards (with the words Parabola, Circle, Ellipse, and Hyperbola) and eight formula/reference cards (with all the a's, b's, h's, and k's explained).

Each day students learn the characteristics of a new conic. Then they separate, sort, and match the corresponding cards. Each deck is different, so they work with different cards each day. One of my students says to me, "I love this, I wish we could learn all our math with decks of cards".

Each card has a letter, number, or symbol in the corner. There is a key for each deck so you can check for correctness at a glance.

At the end of the investigation (which takes 6-8 days), students can identify conics along with their vertices, opening, center, radius, major/minor axes, and asymptotes. And they can sketch them.

I don't go into any more depth than that at the Algebra 2 level. I think advanced students could do the matching more quickly, and you could follow up with some more in-depth study of all the formulas for the formulas. At our school, I leave that to the Precalc teacher.

I have had some contact with Cindy since NCTM, and recently I asked about her policy for sharing the cards. I have no desire to take credit for Cindy's great idea, I just want to help spread it far and wide so that others can benefit the way my students and I have. She said I could share her email, so here it is. You can send her a note to request the Conic Card files. Thanks a million times, Cindy!

Update August 1, 2014:  Cindy's cards are now available on google drive!

Also, I am linking a follow-up post.


  1. I'm teaching Algebra 2 for the first time next year and I want to steal this idea but I don't even understand it myself! lol So this is my IOU a bunch of questions when I am at the point to even think about Algebra 2!

  2. Amy -

    I e-mailed Cindy and just got the files from her. I haven't looked over them yet, but is there anything about changing from general form to standard form? The whole completing the square bit?

    Just wondering! I'm looking forward to seeing what these are about!


  3. Hi Kristen! There isn't anything about complete the square. At our school, I use the cards in Alg 2 to introduce conics -- then they go more in-depth in precalc. I think you could easily use the cards as an intro and then extend beyond that. Amy

  4. I can deal with that :) Also, do you do any instruction before you hand out the cards? Or do you just give them and go?

    I just made my copies (found some pretty colors of paper!) and am ready to laminate and cut. Now I'm just hoping I can find a bored student to do that for me. :)

    Also, are you on twitter? If not, you need to be!

  5. I am on twitter, (sqrt_1) but I have been kind of resistant because the real-time aspect feels too demanding to me. But I have been lurking and @druinok has been drawing me in. :)

    Did Cindy send you her outline? She has it broken down as to what questions she asks and how she has them sort the cards each day. This year, I wrote up some instructions so the students could do most of it on their own. (I can share those). Then I had them take a few notes along the way. You will probably want to go faster than the outline, though, so you have time for other stuff. Like anything else borrowed -- you end up modifying it and making it your own. :) Amy

    p.s. (You definitely need a student to help with the cutting, there is a crazy amount!)

  6. If you wouldn't mind sharing your additional instructions, I'd love to see them! Cindy sent me her outline... I really just need to sit and sort through stuff and figure out exactly what's going on.

    Thanks again! I hate doing conics, so I'm hoping this will help pep them up a little bit :) Especially with just a month left in the school year!


  7. Hi,

    I am student teaching this coming semester and I will be teaching conic sections. This looks like a wonderful activity. Would I be able to receive the additional instructions, notes, questions, etc.?

    Thank you!
    Kristen (#2)

  8. Hi Kristen! Have you emailed Cindy Johnson to ask for the cards? I think everything is explained pretty well in her materials, and she has always been happy to share with anyone who asks.

    I did a follow-up post here where I share some resources I've made:

    If you can't get those to work or you have more questions, you are more than welcome to email me: and I will try to help. :)

    Best of luck with your student teaching!