Posted in Math, MTBoS, MTBoSblogsplosion

My Favorite Topic: rate of change

I can say with confidence that my favorite topic in math is rate of change and/or slope.  I love talking about slope because of the ease to find real world applications, the fun activities I deploy in class and the low floor and high ceiling when it comes to teaching this topic.  I’m not sure if it is a benefit or a drawback to our high school curriculum that the idea of slope turns up in all of our required courses (Algebra I, Geometry, Algebra II).  Additionally, I love what I get to do with slope in my Statistics class.  Here are some of my favorite activities related to slope.

Slope Simon Says

I cannot claim this activity as one I created.  It falls under the “beg, borrow, and steal” mantra I accepted as a student teacher.  Anyway, the activity works like this.

  • have students stand up
  • review the basic rules of Simon Says (it is Ms. Stone Says in my class, but I digress)
    • have to say Simon says or you are out
    • have to do the correct movement or you are out
    • flinch and you are out
  • show students what a positive slope looks like

Screen Shot 2017-01-19 at 8.54.36 PM.png

  • show students what a negative slope looks like

Screen Shot 2017-01-19 at 8.54.49 PM.png

  • show students what zero slope looks like

Screen Shot 2017-01-19 at 8.54.58 PM.png

  • show students what undefined slope looks like

Screen Shot 2017-01-19 at 8.55.16 PM.png

  • play the game

Students have ALWAYS requested to play this game more than once and it is so much fun to get out of our seats.


Slope Cheer

I teach my students the slope cheer to help them remember that the y’s go on top.  The words to the cheer are:

READY?  OK!  the change in y divided by the change in x is slope

When I say READY I have all of my students stand at attention and I will wait until the whole class in unison says OK!  Then we make a delta symbol with our arms for the word change in y, a karate chop for divided by, and another delta triangle for the change in x.  I am looking for one of the videos I took of my students doing this and will update my blog if I find one.


Function Carnival

Function Carnival is one of the activities prepared by  When you do these activities the students REALLY get an idea for the meaning of slope.  I love when they are doing cannon man and verbally without prompting ask questions like “how do I make him go slower” or while doing the bumper cars they figure out “how can I make the car stop but not disappear”.  It is amazing to me that I can truly be a guide on the side when I do these activities and REALLY get a good understanding for my students inquiry skills.


Parallel Lines and Desmos

I love when we get to discuss parallel lines and use Desmos for understanding.  I have students “guess” what would make the lines parallel and we discuss how do we know that we have gotten close enough.  Actually, I also love using Desmos to talk about what slope will make the line go horizontal and vertical.


Slopes Are Like People

Sometimes when I have students who are struggling to remember the direction of slopes we talk about how slopes are like people.  I’ll ask “who are my positive people in the room” and after the show of hands I will say something like “positive people walk up right because they are proud an happy, positive slopes go the same way, up and to the right“.  Then I will ask about who are my negative folks, and usually some people will embrace their negativity and I will remark “negative slopes are negative people.  Is there any way to get a negative person out of their negative mood?  NO!?  Well, one would say that negative people are just down right negative”.  Then I will ask for people who are not necessarily positive or negative.  After a show of hands, I will say “people who are not positive or negative are just CHILL” I’ll slowly extend my hands along the horizontal and say “zero slope is just CHILL” and I have my students show me just chill.  Finally, I will ask for people who really don’t feel like they are in any of these categories and say “people who don’t really fit are kinda out of this world.  Point to out of this world.  Where is it?”  Students point up and I say “just like the sky goes on to infinity and those people are out of this world, infinite slope or undefined slope is vertical”.



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