Dan Meyer

Total 1628 Posts
I'm Dan and this is my blog. I'm a former high school math teacher and current head of teaching at Desmos. He / him. More here.

The MTT2K Prize

Let me just point you to Justin Reich’s post on The MTT2K Prize he and I are co-sponsoring and co-judging. I only want to add a +1 and maybe a smiley face next to this sentence:

As far as I’m concerned, MTT2K has brought all kinds of good to the world.

I’d like to see some more of the kind of engagement we saw this last week, the kind where online criticism turns into improved outcomes for millions of students in the span of 24 hours. I’m excited to see what comes of this.

Bill Gates Just Put A Hit Out On John Golden And David Coffey

This strikes me as a really, really effective way to assess the pedagogical content knowledge of new teachers: critique the pedagogy of the Khan Academy video of your choice. You could write an essay and add timecodes for reference or you and a friend could sit in front of the screen MST3K-style and snark your way through Khan’s lecture like John Golden and David Coffey.

I’m really curious how the Church of Our Lady of Technology in Silicon Valley will react to this kind of critique. That church tends to write off most educators’ criticism of Khan Academy as some admixture of jealousy and entrenchment. They aren’t always wrong about that. But the criticism that “this is actually fairly poor lecturing that’ll leave students with shaky procedural understanding and even shakier conceptual understanding” is much harder to refute. It’s also a difficult criticism to illustrate for people who aren’t teachers. This is the best illustration of that critique I’ve seen.

BTW. The low-rent production values don’t do justice to the quality of their concept and critique, though. Thirty dollars on sound equipment would go a long way towards making this a series math supervisors around the US would make required viewing for their inservice teachers.

2012 Jun 20. Kent Haines has eagle eyes and points out that Khan Academy pulled their video within a couple hours of this post. Christopher Danielson asks the right question, I think. Are they pulling the video to correct the mathematical errors, the pedagogical errors, or both. It’s one thing to mistakenly refer to the transitive property when you mean the commutative property. It’s another to teach students that multiplying integers requires the memorization of a bunch of rules that look like magic but just memorize them because okay?

2011 Jun 21. I had high hopes for that comments thread but it wobbled off course pretty fast.

2011 Jun 22. A reader e-mailed asking what kind of audio setup I’d recommend. Here’s what I wrote back:

There are lots of configurations that’ll serve our needs here and probably several that are cheaper or less cumbersome than the one I use to record audio of myself in presentations and lectures. Lately, though, I record video using whatever I have on hand. Then for audio I use:

Then I sync the audio and video in post. Here’s a video explaining the setup.

2012 Jun 22. Khan Academy has re-uploaded the video and the difference is stark. The new version is oriented towards conceptual understanding whereas the last offered you the bare minimum necessary to pass a multiple-choice test or keep your teacher and parents off your back.

An Incomplete History Of The Math Edublogosphere

I'd love for @ddmeyer to write a history of the math teacher blogosphere. He's been around since the very beginning. Dan, will you do it?

I don’t know much about history (” … and Nowak begat Townsley, father of Cornally … “) but here are a couple of observations from a few years of watching math edubloggers come and go.

There are a few crude but useful ways to categorize math edubloggers. Some stay. Others quit. Some blog regularly. Others blog sporadically. Some bloggers construct posts while they’re teaching. Others construct posts after they’ve taught. The first two are fairly obvious, I suppose. The last one is the most interesting to me. You’ll find bloggers who include photos, student work, and other classroom artifacts in their posts as a matter of routine. These bloggers were developing those blog posts – maybe consciously, maybe subconsciously – at the same time they were developing those lesson plans.

Speaking personally, I realized one day that without intending to I had developed a critical community around my blog, a group of people who were willing to save me from my own lousy classroom design choices. They got better at giving criticism and I got better at receiving it. I also got better at posting the kind of rich, multimedia artifacts of classroom practice – photos, videos, handouts, etc. – that facilitated that criticism. I started to plan lessons while wondering at the same time, “What about this is gonna be worth sharing?” Lesson planning and blogging became hopelessly and wonderfully tangled up.

There are generations of math education bloggers that stick together in fascinating ways. Perhaps it goes without saying that math edubloggers start by reading blogs, then commenting on blogs they read, then writing their own blogs. (Not unlike every other kind of blogger, I suppose.) It’s interesting for me to lurk around, though, and see where the new bloggers are commenting. Totally anecdotally, new bloggers seem to interact primarily with a) bloggers who started blogging in their same generation and b) bloggers who started blogging in the previous generation. Confusing? Andrew Stadel and Fawn Nguyen both started blogging about math education at about the same time. They both provoke and encourage each other on their blogs. I also see them interact with Christopher Danielson who started blogging a little over a year earlier. Meanwhile, they comment less often on this blog because, I dunno, I’m some kind of old timer and they’re ageist or something. Basically: new bloggers find community at their own level of experience and they find mentors one limb above them in the math education blogging family tree.

Those are my only observations that aren’t completely obvious. It’s a weird community that is always hungry for personality and wisdom, that occasionally collaborates and supports itself in spectacular ways that knock the wind out of me.

Your summer assignment: jump in.

2012 Jun 18. Matt Townsley has a Google survey which may help us construct a family tree. I added my details. Feel free to pitch in.

2012 Jun 19. And the results of that survey. What does it mean?

[3ACTS] Coffee Traveler

See the task page.

I set up the problem and then had a whale of a fun time figuring out an answer. I suspect I used a railroad spike where a penny nail would have sufficed, though, so I’d like to see how you’d solve it. Leave your method or a link to a scanned scribble sheet in the comments.

BTW: This is another example of the advantages of the digital medium I’m working with. The student sees two images. One looks almost identical to the other.

With the first image, I can ask the student to guess where the water levels falls in the rotated traveler. Then we lay down a mathematical structure on the image and the student works on a more abstract task. But I’ll wager that when people use this task they’ll just print out the second image because, wow, that’s a lot of paper to use for something as fleeting as a guess. That’s an advantage of digital media: students can work on more concrete tasks using more concrete representations, then abstract tasks using more abstract representations. At no extra charge.

2012 Jun 16. From Discovering Geometry, Fifth Edition, pg. 548:

A sealed rectangular container 6 cm by 12 cm by 15 cm is sitting on its smallest face. It is filled with water up to 5 cm from the top. How many centimeters from the bottom will the water level reach if the container is placed on its largest face?

[3ACTS] Popcorn Picker

See the task page.

FWIW, this is exactly the reaction I hoped to provoke with that video:

Featured Comments

Ryan Brown:

This is a classic textbook problem that we actually did early in the year (Discovering Geometry, Ch. 10) and at the time I recall a number of students asking me for help. They weren’t entirely sure what the problem was asking, and they didn’t know where to start. I’m sure a large number of my no-homework doers saw a block of text and skipped it entirely. We did this today, and kids totally bought into it.

brooke:

This was awesome. I just showed my 8 year old and asked, “Which one will hold the most popcorn?” He answered, “Both.” I now need to show the other kids.

2012 Jun 16. From Discovering Geometry, Fifth Edition, pg. 548:

If you roll an 8.5-by-11-inch piece of paper into a cylinder by bringing the two longer sides together, you get a tall, thin cylinder. If you roll an 8.5-by-11-inch piece of paper into a cylinder by bringing the two shorter sides together, you get a short, fat cylinder. Which of the two cylinders has the greater volume?

2012 Jul 2. From Everyday Math. Page One. Page Two.