Multimedia in the classroom

Jack Treuhaft
Algonquin College of Applied Arts and Technology
January 1995

Multimedia in the Classroom

Once you have created a multimedia presentation using Astound, or another package you can show the images to others. You can either project the presentation onto a screen or display it on a television monitor. The method you choose depends upon the purpose of the presentation, the audience size, and the nature of the room. Here are some advantages and disadvantages of each method.

Television monitor

• To use a television monitor a special box called a scan converter is required. The scan converter changes the computer output to a signal the television can display. Scan converters cost between $200 and $2,000. The inexpensive converters require both a box and special software to accomplish the job. The more expensive boxes do everything with hardware. Getting a full computer image of the right color displayed on the television may be more difficult with the cheaper boxes. As with many other things, in life you get what you pay for.

• If you want your audience to sit, listen, and watch your presentation without interruptions the television display is a good choice. People are comfortable being passive while watching the tube. The television also provides excellent color saturation and clear, crisp graphics and animation. Large monitors are easy to see in brightly lit rooms without dimming the lights.

• Television monitors have several shortcomings. Most people underestimate the size of the monitor required. To be seen clearly, very large monitors are required, even for small rooms. Most television monitors are useless in large classrooms. Another problem is that text is hard to read on a monitor. This limits your font choices to large sans-serif fonts.

  Screen Projection

• There are two ways to project a computer image onto a screen - use a gun-type projector or use an overhead projector with a projector panel.

• The gun-type projectors can be desk or ceiling mounted and are quite expensive ranging from $5,000 to $25,000. The inexpensive models limit your presentation to fewer color choices and lower resolutions. More expensive models will handle anything your computer can produce.

• A projector panel is a special box that sits on top of an overhead projector. The panels come in a range of abilities to project colors and resolutions. They cost between $3,000 and $12,000. The $4,000 - $5,000 range will get you a panel that can handle all but the most exceptional classroom requirements. Projection panels require special overhead projectors that use low-wattage lamps to avoid melting the panel. These lamps should produce at least 3,000 lumens to provide as bright an image as possible.

• If you want to be able to pause during your presentation and discuss some point with your audience then use screen projection. People feel more comfortable with a frozen screen than with a frozen television display. The projected image can be made quite large and is easy to view even in very large classrooms. Furthermore, the size of the image can be adjusted by moving the overhead projector closer to or farther away from the screen. Text, graphics, and animation are all displayed clearly and crisply. You may freely choose from the full array of fonts available to you.

• A disadvantage of the projection method is that the image is not as bright as the television image. Overhead projector/panel combinations usually require the lights to be dimmed to produce an acceptable image. In classrooms with only switched lighting it can be difficult for students to take notes under these cconditions. In rooms with bright natural lighting and poor window shades this can be a major problem. Another disadvantage is the higher cost of the panel and the special low-wattage projectors.

  There is no one best way to display your presentation. Educators should have a choice of projection methods depending upon the kind of presentation, the size of the group, and the characteristics of the room.