Everything I know about teaching math I learned on the internet.

Everything I know about teaching math I learned on the internet.

Seriously. Yes, I have a math education minor and a credential, but really, that doesn't prepare you much at the secondary level. Calc III did not make me a better Pre-Algebra teacher. 

But thanks to awesome people blogging, I get to steal some pretty awesome activities. 

This week, my students explored

Robert Kaplinsky's aluminum foil prank

math task after we learned about surface area. In this task, students must discover the cost it would take to foil prank a room. My students spent two 40-minute class periods measuring and calculating and loving every moment of it. Meanwhile, I sat back and just watched and listened. Here are a few of the snippets I heard today:

  • "We're going to have to do some serious math!" Yes, that's the goal of math class. However, this was said with much more excitement than the normal problem set.
    Our funky ceiling tiles 
  • "The surface area of a ceiling tile is 144 sq. inches. Now we need to count the tiles." On their own, my students decided that it would be much easier to just calculate the area of one ceiling tile and then count the number of tiles.
  • "If we have two half tiles, why don't we just count it as one full tile?" I love how math and problem solving became a discussion in this activity. They started talking through what they were doing.
  • Student A: "1 yard, 12 inches." Student B: "Yeah, 4 feet." Student A: "Yeah, 4 feet." Working together and helping each other understand! 
  • "Ugh... my brain's exploding!" My students have a love/hate relationship for math tasks. But as a teacher, I love hearing that their brains hurt.
  • "One light is 192 square feet. Just by looking at, I think that's wrong." I loved that this activity made the surface area questions real for my students. They could understand the validity (or lack thereof) of their answers. As we worked it out, we realized the importance of our units. When we multiply the area, we end up with a squared unit. Throughout the process they were changing a lot between inches, feet, and yards, and when they were doing that with area, they forgot to do the unit conversion right.
  • "Can we leave this on the board until after everyone comes in?" They were so proud of the work that they did the past two days, and that's just plain cool. I'm typically an English teacher, so having math on my board is weird, and it definitely elicited a response out of their classmates the next period when the whole class came to me for English. Things like... "Woah... complex math." Another student not in my math class exclaimed, "That looks fun!", to which one of my math students said, "It was fun. A lot, a lot of fun."

Honestly, we didn't even get through the entire task, but we spent the last five minutes of class talking about what they learned in the process, and it was so fun to hear their metacognition. We counted that we touched at least seven of our math lessons by doing this task. They definitely have a deeper understanding of surface area and converting units too, which is sweet. 

A few ideas I'd try next time:

  • I'd make it a smaller area. I only have five students in my math class, and my room is pretty big. I'd like it if they spent a little less time on measuring and more time calculating. I think I really want to do our principal's office or one of our prank-loving teachers. 
  • I'd go digital with some of the data. It sort of drove me crazy how unorganized their data was. I think they remeasured the same things many times. I'd consider combining with a Google Sheets lesson to talk about organization and equations. 
  • As a follow-up activity, I'd wrap a few objects in tinfoil. Is the surface area really the amount we need? Or do we actually need a little more than that. 

But in all seriousness, thanks to Robert Kaplinsky and all of the other amazing math educators out there sharing their ideas. I really would be nothing in the math class without them. Keep blogging, people. I need you.