Wednesday, November 17, 2010

"When will we ever use this?"

At my school, there's a huge emphasis on "adult-world connection." A question that teachers (or at least I) often hear when introducing a new concept is "How is this used in the real world?" (As an aside: How much do teachers at other schools encounter this?) Last year, I taught 11th grade math: an ill-defined combination of pre-calculus, algebra II, statistics, and random topics that don't really fit into any standards. I tried to create projects that touched on several different applications of math (such as linear programming to solve a land use problem, and statistical analysis of a survey the students created). Granted, I'm sure I could have done a better job creating and executing projects, but based on my limited experience I came to the following conclusion: real real-world math is really messy ... mostly too messy to survive the attention span of the average high schooler. So the real-world math we did was really fake real-world math. And guess what? The students totally didn't fall for it. It felt like a completely contrived textbook word problem that was extended into a month-long project.

Lately, I've been feeling that the question "How is this used in the real world?" is a bit misguided. Sometimes there is a really good answer that fits into a 2-minute sound bite without completely disrupting the flow of your class. Quadratics are the classic example of this: How will you ever know where your rocket/football/rubber chicken will land if you don't understand projectile motion??? However, once you step into the realm of calculus it's difficult to encapsulate the usefulness of something like the derivative in 5 sentences or less. (Or not ... please let me know if I'm totally off-base here!) Most often, I find myself wanting to give one of these two responses to that dreaded question (although I never would):
  1. Asking how [insert complicated math concept here] is used in the real world is like asking how multiplication is used in the real world. It's everywhere, but could you sum up how it's useful in 2 sentences to a fourth grader who was just learning his times tables?
  2. The real-world connection is that you're going to have to be able to [insert tedious technical skill here] in order to pass your intro-level calculus/physics/engineering classes in college so that you can move on to bigger and better things.
  3. Does it matter??? Can't we just do it because it's interesting in its own right? A little abstract thinking never hurt anyone! (Shockingly, this argument doesn't actually seem to make concepts more interesting.)
My point is that its connection to the real world is only one (small) reason why I love math. What I really love is the feeling of success when I finally figure out something that I never thought I'd understand. I love discovering beautiful patterns. And yes, I sometimes even love the rules and the stability that they offer in the midst complete chaos. I'm also convinced that (most) high school students don't really want to learn about real-world math, except for maybe the occasional pretty picture of a fractal or 2-second snapshot of some grotesque computation that is used to solve a "real" problem. Instead, they (like all of us) just need a hook. Usually that hook is sinking their teeth into a problem that captures their attention, not doing a "realistic" mathematical analysis.

Don't get me wrong -- I do want my students to understand why mankind has spent hundreds of years studying the derivative. I want them to understand the equations of motion, and optimization, and differential equations -- but it's going to take an entire year of calculus to really answer that question, and I'd rather answer it well in a year than answer it superficially in 5 minutes. In the mean time, I can try my best to make the concepts engaging in their own right so that my students want to learn them, even if they don't instantly see the "real-world connection."


  1. Yeah, I agree. When I talk to my calculus students, I actually tell them that they aren't going to use calculus in their everyday lives. They're not going to the grocery store and computing the optimal can. They're exploring something interesting and strange and beautiful. It's like Shakespeare -- he doesn't have "everyday use" but he's culturally rich. My goal is for them to see that. I fail most of the time. Sometimes I succeed.


  2. I think one of the great things about math is that it generally sharpens your mind. While most people will probably never use the math they learned in school, hopefully they have gained the ability to think more clearly about whatever it is they are passionate about.

  3. Sam - I have to say that I was a wee-bit star-struck when I saw that you commented on my post. Thanks for reading my blog!

    I want to share one more opinion on this matter from one of my colleagues who teaches English. His response to "How will I use this in my life?" is "What kind of life do you want to lead? The life of a brute, or the life of someone who appreciates the richness of Calculus and Shakespeare?"

  4. Good thoughts. Especially considering that you just finished your second year of teaching (if I'm reading correctly). Upon finishing my second year of teaching the only thing I was feverishly searching for was sleep.

    I agree with you, and have a post in the making about the importance of a hook and about how catchy real world (actual real world, not clip art in a math book) truly is.