Wednesday, February 27, 2013

Bring coding to your students

I’ve griped before about the lack of computer programming opportunities that our students have today.  Here’s a free and painless way for kids to get started – something you could devote one period to (to hook the intrinsically motivated), or build an entire curriculum around:

Wednesday, February 13, 2013

Visualizing music

After besting me at snowflake making recently, Vi Hart came out with one her best video ideas to date, in my opinion.
Playing with the symmetries in music in a visual way, she reminded me of the visualization I made for Bach’s “Crab Canon,” which sounds the same forward as backward and “looks” like this:
crab canon2
I’ve always been a fan of music visualization videos because they allow you to appreciate some of the patterns, structures, and relationships (what we might call “math”) that you may otherwise miss.

Monday, February 4, 2013

Quilted geometry

A few years ago my mom began work on a quilt for my wife and me.  I had the opportunity to design it, and went with something less common than the right triangles and squares you see on a lot of quilts:
quilt design copy
This is an example of an Islamic tile pattern featuring 5- and 10-pointed stars. 
Getting the pieces cut out proved to be challenging.  After some puzzling, I found that the design could be created using two rhombus-shaped “stamps”:
quilt design copy2
You could estimate the lengths involved, but exact answers are so much more satisfying.  I can’t quite remember how I went about calculating the proportions, but I was happy to find the golden ratio Φ featuring prominently in them:
It turned out pretty cool, don’t you think? 

But I hope you’re not in a rush to get yours – the hand quilting takes a long time.

Friday, February 1, 2013

One "type" of problem

Sometimes displaying math text on the web is a pain.  There's LaTeX, but it's a hassle to employ in Blogger.    You can render your expressions elsewhere and use images, but I think the MathML code provided by Web Equation works pretty well if you don't mind writing your expression on the screen.

It did glitch on me a couple of times and require a page reload.

Here's a quick example:

 x = - b ± b 2 - 4 a c 2 a