Pick A Point

Here’s my favorite moment from a workshop in Spokane last week:

It’s about the quickest and most concise illustration I can offer of Guershon Harel’s necessity principle. The moment of need is brief, but really hard to miss. It sounds a lot like laughter.

2014 Feb 19. Christine Lenghaus adapts the interaction for naming angles:

I drew a large triangle and then lots of various sized ones inside it and asked the students to pick an acute angle. I asked a student to describe the one they were thinking about and then another student to come up and mark it! This lead to discussion on how best to label so that we both agree on which angle we were talking about. Gold!

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Joel Patterson:

Thereโ€™s an easy way to do this in Geogebra.
Open up blank Geogebra file, viewing only the Geometry window (no Algebra window).

Click the point tool and make a bunch of points like in Danโ€™s video.

Then there is a small button AA with one A in black and the other in grey. This button shows and hides labels for all points.

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Hans Freudenthal:

Youngsters need not repeat the history of mankind but they should not be expected either to start at the very point where the preceding generation stopped.

2017 Oct 16. Here are the slides.

[Fake World] Culture Beats Curriculum

a/k/a Worshipping The Real World

Here are three e-mails I received from three different people over the last three months. Spot the common theme.

November:

My co-teacher and I were puzzling over what kind of problem would create an intellectual need for systems. Do you have anything you could send, by chance?

December:

We are planning to launch a unit on systems of equations in early January (after December break) and wanted to try out your approach to create an intellectual “need.”

January:

Showing two straight lines on a piece of graph paper and finding points of intersection has very little significance to most people. I’m looking for a real-world problem that has an answer that is not self-evident, but which requires a little thinking and finding the intersections and is infinitely more productive and satisfying and will stay with them for the rest of their lives. That is what I am looking for.

I receive these questions on Twitter also. I find them almost impossible to answer because I don’t know what your class worships.

Here’s what I’m talking about:

Class #1

You start class by asking your students to write down two numbers that add to ten. They do. Most likely a bunch of positive integers result.

Then you ask them to write down two numbers that subtract and get ten. They do.

Then you ask them to write down two numbers that do both at the exact. same. time. “Is that even possible?” you ask.

Many of them think that’s totally impossible. You can’t take the same two numbers and get the same output with two operations that are natural enemies of each other. They’d maybe never phrase it that way but the whole setup seems totally screwy and counterintuitive.

Then someone finds the pair and it seems obvious in hindsight to most students. We’ve been puzzled and now unpuzzled. Then you ask, “Is that the only pair that works?” knowing full well it is, and the class is puzzled again.

You define systems of equations as “finding numbers that make statements true” and you spend the next week on statements that have only one solution, that have infinite solutions, and the disagreeable sort that don’t have any solutions.

Students learn to identify the kind of scenario they’re looking at and how to find its solutions quickly (if any exist) using strong new tools you offer them over the unit.

Class #2

The same lesson plays out but this time, after we’ve determined the pair of numbers that solve the system, a student pipes up and asks, “When will we ever use this in the real world.”

Worshipping the Real World

David Foster Wallace wrote about worship โ€” the secular kind, the kind that applies to everybody, not just the devout, the kind that applies especially to us teachers in here:

If you worship money and things โ€“ if they are where you tap real meaning in life โ€“ then you will never have enough. Never feel you have enough.

If your students worship grades, they won’t complete assignments without knowing how many points it’s worth. If they worship stickers and candy, they won’t work without the promise of those prizes.

If you say a prayer to the “real world” every time you sit down to plan your math lessons, you and your students will never have enough real world, never feel you have enough connection to jobs and solar panels and trains leaving Chicago and things made of stuff.

If you instead say a prayer to the electric sensation of being puzzled and the catharsis that comes from being unpuzzled, you will never get enough of being puzzled and unpuzzled.

The first prayer limits me. The first prayer means my students will only be interested in something like The Slow Forty โ€”ร‚ย a real world application of systems. The second prayer means my students will be interested in The Slow Forty (because it’s puzzling) but also the puzzling moments that arise when we throw numbers, symbols, and shapes against each other in interesting ways.

The second prayer expands me. Interested people grow more interested. Silvia writes, “Interest is self-propelling. It motivates people to learn thereby giving them the knowledge needed to be interested” (2008, p. 59). Once you give your students the experience of becoming puzzled and unpuzzled by numbers, shapes, and variables, they’re more likely to be puzzled by numbers, shapes, and variables later. That’s fortunate! Because some territories in mathematics are populated exclusively by numbers, shapes, and variables, in which cases your first prayer will be in vain.

That’s why I can’t tell you what to teach on Monday. Your classroom culture will beat any curriculum I can recommend. I need to know what you and your students worship first.

BTW

References

Silvia, PJ. (2008). Interest โ€“ the curious emotion. Current Directions in Psychological Science, 17(1), 57โ€”60. doi:10.1111/j.1467-8721.2008.00548.x

[Confab] Design A New Function Carnival Ride

The early feedback on Function Carnival has been quite kind. To recap, a student’s job is to graph the motion on three rides:

But we found ourselves wondering if there were other rides and other graphs and other great ideas we had missed. So we’re kicking this out to you in this week’s Curriculum Confab:

What would be a worthwhile ride to include in Function Carnival? What would you graph? Why is it important?

I’ll post some great responses shortly.

Previously:

In the last confab, we looked at a math problem inspired by Waukee Community School District’s decision to let their buses idle all night. Molly showed us how to make a good problem out of it, and a lousy problem also. Great confabbing, people.

[Confab] Snow Day

Earlier this week, Matt Reinhold tweeted:

Fearing our buses wouldn’t start due to cold, our district let them idle overnight. The first student question this morning: “How much did that cost?”

  1. That’s kind of amazing.
  2. There’s a local, personally relevant, real-world math problem somewhere in there for students to work on and learn from. But one of my theses with fake-world math is that relevance and the “real world” aren’t necessary or sufficient. They don’t guarantee interest and they don’t guarantee learning.

So tell me about an effective treatment of this situation in math class. (Draw on research on curiosity, abstraction, and the CCSS modeling framework if they’re helpful.) Also tell me about an ineffective treatment of this situation in math class.

BTW. “Curriculum Confab” will be a recurring feature around here, similar to our early “What Can You Do With This?” days only with more design and theory attached.

2014 Feb 02. Molly helps out enormously with this confab:

Ineffective: If gas costs 3.38 per gallon, and the bus burns 1.1 gallons per hour idling, what is the cost of the fuel burned by 32 buses over a period of 13 hours?

Effective: 1. What questions do we need to ask in order to answer this question?

The first treatment offers no “information gap” of the kind that’s generative of student curiosity. Moreover, curious or incurious, the first treatment doesn’t have students doing modeling of the sort promoted by the CCSS, where students set themselves to “ identifying variables in the situation and selecting those that represent essential features.”

I’d only add one question to Molly’s effective treatment: “How much would you guess it cost the district to keep the buses idling overnight?”

Ask And Ye Shall Receive

So this is fun. Last week at 10:50AM I asked the world to make me two websites:

An hour later the world delivered one of them:

Eleven hours later, the world delivered the other one:

I wired up those domain names to the blogs Rebecca and MathCurmudgeon registered and now we’re in business. Two more sites for our pile of awesome single-serving sites:

Be a pal. Subscribe and submit ideas.