For my first semester as a student teacher, I taught 6th grade math. Many of my students had a hard time controlling themselves, and one of my standard tactics was to make a list of offenders I would make stay after class. A very common problem, and a common way to handle it. But it was obvious that the clearer the connection between the behavior and the consequences, the more effective a deterrent it was. So my partner and I started putting a timer on the smartboard to keep track of how much class time the offending students had wasted, and announcing that they’d be staying after class for the same length of time.
To make the connection even more concrete, I looked for a simple, easy-to-use program that would count down whatever length of time it had gotten up to, and preferably one that could run in a Web browser with no installation. But I couldn‘t find one: every program I ran across treated going up and down as unrelated functions, typically calling them “stopwatch” and “timer”.
Well, I know how to program a computer: I spent years working as a software engineer. So I finally (long after my semester in middle school) wrote it myself. Following a suggestion by my friend and colleague Jeremy Sebens, you can even set a time of day — the time the class ends is the obvious candidate — at which it’ll start counting down automatically!
“Don’s Up/Down Timer” is available at
There are also instructions for using (and, if you want, customizing) it there, but it requires no installation and it’s very easy to use.
Another classroom application might be the opposite of the above scenario: you want to reward students for doing something they don’t like — and the longer they do it, the longer they get to do something they do want to do.
I think Don’s Up/Down Timer would be most helpful in middle school, but it could be useful in any situation where you want to measure an unknown interval of time, then set a timer to go off when the same interval elapses again. Prof. Kathy Marrs of IUPUI tells me she’s used it with her college-freshman biology class — I’m not sure for what. Certainly there’s nothing specific to math about it.
(4 Feb. 2013: revised to add the “rewarding” application and update the URL.)