You’ve probably seen one of these at a conference, but you may not have considered using it in your classroom. Sometimes my students don’t plunge into a time-limited task as quickly as I’d like. To encourage them to use their time wisely—and limit boredom and off-topic chatting—I keep intervals short and rigidly adhere to the prescribed schedule by using an on-screen timer. Typically, the first segment ends up being less than ideally productive, but students quickly become more efficient as they realize that Chaucer was right: “Time and tide wait for no man.” Or woman, because that darn timer is ruthless.
A quick web search offers a variety of timers. I especially like the one at http://www.online-stopwatch.com/countdown-timer/