Sunday, 27 October 2013

Quadratic Headbanz

My grade 10 academic math class is filled with great kids.  For the last week or so we have been exploring quadratics in vertex and factored form, with the help of Desmos.  My students are pretty solid at going between equations and their graphs.  On Friday, about half of my class was away on a history field trip. We finished some questions from the previous day but I didn't want to start anything new - I wanted to do something fun!  At TMC13, Sam Shah organized a Rational Headbanz game for the pre-calc group and I thought I could modify it for quadratics.

With the help of my colleague, Michelle, we made 30 headbanz.  We used coloured card stock, cut into rectangles with 2 slits cut along the sides to accommodate ribbon.  I wrote the equations and this is how they turned out:

The kids were pretty excited to play.  I like to have written instructions on top of what I say, so here is what they saw:

They each got a whiteboard to record their work.  It was interesting to see them thinking about what to ask.  Many started with "Am I in vertex form?" or "Am I in factored form?" but the poor student who had  had a hard time getting good answers.  They had to think about what questions to ask.  The nice thing is that those who were struggling heard the questions others were asking them and were able to move forward.  The trickiest part was with the value of h in 

They would ask "Is my h value positive?" but then either interpret the answer incorrectly or not be sure whether the person they had asked truly understood what a positive h value meant.

They all figured out their equations and had fun doing so.  And they want to play again next week when the whole class is there.  I'll be happy to oblige.

Thanks, Sam, for the inspiration : )


  1. I love this! Thanks for sharing; I think it could be adapted for so many topics. What happened when they figured their equation out? Do they get another one, or did it take the entire time of the activity to get just one?

    1. They just did one as it took a little while for them to figure out their equation. However, it is quick enough that we can do it again to keep practicing quadratics.

  2. Hi! I want to do this with my students, great great idea!! But I'm wondering what questions do they have to ask to know the "a" parameter? They have to know a point to find it but the answers can only be yes /no!?

  3. They asked if 'a' was positive/negative, then narrowed in on it... "Is 'a' between 1 and 5?" Seemed to work better than I would have thought!

  4. What would happen if half of the students had the actual graphs and they had to find their partner?

  5. wow,,awesome. this is an interesting idea that i want to try. Thank you Mary :)