Jan 13

The 3 States of H20

This isn’t on topic, but it was so cool I couldn’t help myself. I have a side venting furnace that sends moist exhaust out. There is a metal cap on the end of the vent. That metal is quite cold at the moment (January in CT) and condenses some of the water vapor into water. The water in turn falls on the ground and freezes on the cold driveway. I was going for a walk the other day and noticed the 3 phases or H20 happening right in front of me. Okay, I geeked out, but my question is, is this a physics or chemistry geek-out, or both? Oh, and this video was a couple of days ago. By now the little ice cap on the ground is like a reverse icicle.

Oct 12

TED + Math

I was searching for something else and got sucked in by this provocatively titled TED vid, Why Math Instruction Is Unnecessary. It was a well spent 12 minutes. It basically follows how a middle school math teacher’s answer to the question, When will I ever need this?, has evolved over time.

Sep 12


math tv
I’ve been mashing up web resources for my College Algebra class this semester. For the most part, I stick to Khan academy videos because students tend to like them and the library is so extensive. On some topics, I’ve been pushed out onto the web to supplement. One of the best math video resources I’ve found on the web is MathTV. There are a couple of things I really like about it. One, videos are introduced by the problem not by the topic. I have noticed, when pushing my students to find web resources on their own, a huge block for them is coming up with the relevant search terms for the skill e.g. simplifying complex fractions. However, they are much better at recognizing when a problem is similar to the one they want to solve. Therefore, MathTV makes it easier/faster for them to find what they are looking for. The second reason I like MathTV is they have multiple explanations of the same problem by different tutors. Sometimes there is even a Spanish language option.

math video demo

The frustrating thing is that I can’t link directly to a list of videos on a particular skill. You can see them altogether, but there isn’t a unique URL for that view. They have a playlist creation function on the website that didn’t work very well that is supposed to accomplish this. But even if it did, that is a lot more work than I want to do. It would be nice to copy the link for “absolute value equations” directly from my browser, and then paste it into my discussion system.

Aug 12

Math + Mind Tickle

I place $20 in a box.
So do you.
Now the box contains $40, and we both know it.
I sell the box to you for $30.
And we both walk away with a $10 profit.

Jay sent over a link this great problem. It’s from one of my favorite blogs Futility Closet. This is the perfect kind of problem to throw out in class…easy to remember and easy to think through in a few minutes. What’s lovely is that initially it seems so plausible and yet impossible that they both profit $10. It reminds me of a Nova show (embedded below) I was watching on neuroscientists studying magic. Most tricks rely on our visual system’s strong bias toward detecting and anticipating motion. I feel like this problem and ones like it trick our reason, possibly with the momentum of language? Whoa, that got deep! Better stop right there.

Watch Magic and the Brain on PBS. See more from NOVA scienceNOW.

May 12

Now Playing: Numberphile

I’m loving this Youtube channel, Numberphile. It might be a way to try to bring some media into the classroom in a non-boring way. I hope they’ll get students to wonder about math in a more general non-skills based way.

Apr 12

Geometry + Sound

I found this stunning visualization on open culture.

Apr 12

Miura Fold

miura fold
I came across the Miura Fold on Lifehacker. It basically allows one to fold/unfold something with a single motion. The easiest way to think about the value of the Miura fold is in terms of a map. I can’t count the number of maps I’ve screwed up by not folding it back up the right way. Unfortunately it’s fairly hard to learn the fold. I have to build up those origami skills.

Feb 12

Math + Running

I found this via free tech for teachers. What a lovely combination of math and science working together to demonstrate something rather non-obvious: learning to run without shoes helps reduce the impact of running on your body. The one thing they didn’t show was what someone that learned to run without shoes looked like running in shoes. Would it be even smoother?

Nov 11

Math + Unblievable

A couple of my students told me about this guy–the human calculator. There are a lot of tricks to doing mental calculations quickly. This guy is unbelievable though.

Thanks Dan and Matt!

Sep 11

Math + Rap

My Facebook friends gave this video some serious love. It is definitely a novel way to teach factoring. Other hits from Westerville South High School include, Getting Triggy With It and Do the Quad Solve. Just try not to dance :)