When asked which digital technology was most in evidence in their classroom, today's high school and college students report that it's PowerPoint: a slide show that their teacher projects on the screen, a progression of bullet-points parading from the projector. When I query college professors on which programs they use the most in the classroom, most hands rise at the mention of PowerPoint.

The ubiquity of this technology in our classrooms demands a closer look. Why do we use it so much? What effect does it have on our teaching? On the nature of the classroom? How might we use it better? This week's article attempts to respond to these questions.

"The projector broke, and there was no way to fix it. So I had to run my class without PowerPoint. I was worried that it wouldn't go well. But it turned out to be a godsend. I found myself digressing from the script, engaging my students in conversation, wrestling with important ideas. We looked each other in the eye. It was like the good old days. I was surprised. The students hung on after the bell, we talked, we never came to a conclusion."

"This made me think. What was teaching like before PowerPoint? What has PowerPoint done to my classroom? How has it affected my teaching?"

"For the next class meeting, the projector was fixed, but we hesitated. 'Do you want the slides, or do you want to talk?' I asked. They wanted to talk. About PowerPoint. Without benefit of bullet-points or backgrounds, we talked about what PowerPoint has done to us. We concluded that we have let it change the nature of teaching and learning in the classroom. With PowerPoint, my task has become to get through the slides. The students' task has become to write down what's on the slides. Before PowerPoint, our tasks were different: mine was to explain the topic at hand; theirs was to understand it. PowerPoint effected a subtle change in the nature of my classroom."

I've heard a story like this from many teachers. At first, PowerPoint seemed helpful, enervating, an organizing force, a new way to hold students' attention, a modern way to keep track of the topics. But over the years it almost imperceptibly moved teaching in a different direction. The medium modified the message. "We shape our tools," wrote Marshall McLuhan in 1964, "and then our tools shape us."

Into what shape does PowerPoint mold our classrooms? Teachers and students alike claim that as most often deployed, these slide shows send us toward linearity, exposition, and transmission, and away from interactivity, spontaneity, and discussion. The way that PowerPoint comes out of the box, with its default titles and bullet points, encourages us to organize our teaching into a series of similar slides full of text. And the big screen in the classroom on which it is displayed becomes the center of attention, stealing the limelight from the students and the teacher. We're all looking at the screen instead of each other.

Think of the classroom as a theater. In the old days, you were on the stage, the audience in their seats, the interaction between the two direct and simple. Then one day a new actor appeared with you, eight feet wide, six feet high, stage-center, colorful and well-lit. You wrote the script for this actor. But did you take the time to outline his character, define his role, or craft his interaction with you and the audience? Had you done so, you might have written a very different play.

PowerPoint Playwright

Picture Hamlet and Ophelia on the stage in scene 5 where they confront each other with accusations of love and madness. But instead of the complementary back-and-forth repartee that makes this masterful drama, Ophelia instead holds up a cue card that repeats in bullet points everything that Hamlet says. That's what we are doing most of the time when we lecture with PowerPoint. We use the new actor on the big screen repeat in text what we say with our voices, hardly a creative use of the setting or of the technology, hardly fun for the audience.

Good actors complement each other, one providing the quid as the other provides the quo, one making a point as the other reacts to it, the protagonist and his foil, both aimed as much at the audience as each other. Let the PowerPoint on the big screen complement your words and actions. let it provide the things you cannot. Let it play against you now, in harmony with you later. Treat it as a fellow actor on your classroom stage that you can work with to provoke your audience and get them involved in the action. Don't fall into the trap of always programming him to parrot your lines or to summarize your soliloquies.

In most classroom situations, our strength as a teacher is the spoken word. The key strength of the big screen is the image. A good way to play both actors to their strengths is to ban text from your slides. Use only images. rewrite the role of your PowerPoint personage to provide images that complement, illustrate, illuminate or oppose the words you are speaking. As your students listen to you, they watch pictures on the big screen that if carefully chosen can amplify and deepen your voice. PowerPoint has his lines, you've got yours, and when both mesh well the audience thrives.

For ideas on how to use images in this interactive way, see The Power of Images in this series.