Monday, March 19, 2018

Cup Stacking Lab

I came across this post by Andrew Busch and hit the jackpot for all things linear! Within this post were a couple of lessons I have used and some that I have seen other bloggers talk about. The one that caught my eye was the cup stacking. When looking through the new Illustrative Mathematics at this unit, I saw the cup stacking lesson and knew it must be meaningful. I went back to that post and read about how Andrew Stadel and Dan Meyer ran the lesson. In my search, I found where Sarah Carter had also used this lesson for rate of change. This {had} to be my next lesson, or math lab, as I have called them this year! 

The math lab started with the simple question, "How many cups would you have to stack to reach the height of me?" After students threw out some guesses on whiteboards to get us started, I stacked five cups beside me for them to start visualizing. I wanted to draw out questions to get them thinking as well as ask for supplies they needed. Students already knew my height because they have been measuring themselves on the growth chart all year. They had to convert inches to centimeters but Siri gave them that information in 2 seconds!

Once they had my height in centimeters (152.4 cm), they tried several different strategies to make another guess at how many cups. Some students looked at how high five cups reached when next to me and then eyeballed how many more it would take. You could actually see their heads bobbing as they counted by fives from my chins up! At this point, I gave each group five cups. You can see below that this group measured the height of the five cups then used that height to make a table. 

This group, and a couple others, did not take into account the cup has two parts that have to be considered when calculating the height of the stack. A common misconception was for students to measure how much the cup is increasing and then divide my height by that number. 

Many groups recognized the two parts to the cup and figured out how to use them. They did not create an equation but they did exactly what the equation would have done. Once I walked them through writing the equation, they were able to see that we could put any amount of cups in and find the height or find the number of cups by substituting the height. It was amazing watching their thought process to figure out this problem!

I had help stacking the cups {my helper was dying to see if his group's guess was correct so he jumped up to help}! I stopped at each guess we had that was lower and asked if anyone wanted to change their guess. Students were excited watching us stack the cups waiting to see if their guess was correct!

The room was filled with "yessss" and high fives when the cups were stacked to my height! After the stacking, we recorded all of our thoughts in our notebooks. Students were able to see the rate of change and the initial value and how they came together in the equation. 

This was a great bridge from rate of change to slope-intercept. It gave students something concrete to reference when talking about initial value, y-intercept, and slope. You could do this lesson as a 3Act with the videos in the links above or use Illustrative Mathematics' take on it as a guide. 


Saturday, March 10, 2018

RC Car Lab for Slope

This year, I have been experimenting with math labs for my students. I saw students learning math concepts in their science class, so excited about labs and how they were collecting and analyzing real data. I knew I wanted that for them in my math classroom as well. Science can't have all the fun!

Helping students understand slope is a big deal in 8th grade. The idea of rate of change requires a depth of understanding well beyond "rise over run." In order to help students better understand the concept, they need to be given real-world opportunities to connect the abstract concept of slope with physical situations. Cue the RC Car Math Lab! 

I started the lab by showing them the cars and asking how we could determine how fast they would go. They had learned about speed in science {because that's how science and math play together} so they were able to determine the variables. I explained how they were going to collect the data with stopwatches at different intervals. I fudged the numbers for distance a tiny bit so it would be somewhat linear but don't tell my students! 

You can see the team above with all of their stopwatches ready to get the time when the car crosses their line. One team leader made me laugh because he made his group give their times in order of distance. They could not just call out their times willy nilly. He was very adamant about this!

One of the challenges with this lab was finding a driver! Not everyone could drive the cars straight to get good data. After the first class, I let them have a few minutes to all play within their groups and decide who would drive. The trials ran much better by doing this. 

Each group did three trials and then we came back inside to analyze the data. Once the speed of the RC car was determined, students were tasked with finding how long it would take to get to the beach in the little car. 

This lab gives us another experience that can be referenced when we talk about slope intercept form in different contexts later on. And students had a super fun day in math lab!


The Most Dreamy Pencil Sharpener Ever

As a math teacher, pencils are a really big deal in my classroom. We have all had the struggle of pencils in our classrooms! You know what I am talking about, sharpeners that break or eat the entire pencil in one sharpen, the sharpener that interrupts even the class down the hall it is so loud, a sharpened pencil that the lead falls out or breaks as soon as the student gets back to their seat and writes one thing! With this pencil sharpener from Classroom Friendly Supplies, all of those struggles are over!

We were down two electric sharpeners and all the cute handhelds to a single sharpener students had to hold over the trash to sharpen! It was a sad story so I started searching for a replacement. I remembered seeing posts about this amazing pencil sharpener and did a quick google search and found it. The most dreamy pencil sharpener ever! I truly cannot say enough awesome things about this sharpener.

Look at that happy math student because of the sharpener! I gave a quick demonstration to each of my classes to show them how it worked.

My office manager was super excited to have a real sharpener. One of the office manager's job is making sure the pencils that are borrowed are returned and sharp for the next class each day. It is a very important job and my office managers all appreciated the new pencil sharpener.

The students even shamed the other teachers on my team by raving about our new one! I have been singing Troy's praises for letting me try one out. He is the owner of Classroom Friendly Supplies and is also a teacher. Maybe that is why he knew the value of having a super dreamy sharpener in a classroom.


If you are in need of pencil sharpener that makes no noise, sharpens pencils to a solid point that does not break, and that students will rave about, get over to Classroom Friendly Supplies and order your classroom one. Or join with some teacher friends and place an order to get a great discount.

The most dreamy pencil sharpener ever! Happy sharpening!

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