_Pushbuttons and Such._ Few audience-participation devices in science fair exhibits merit the effort, money, and space expended on them. But if you do display equipment for viewers to operate, make certain it can be operated safely and dependably even when you are absent (as during the judging). Nothing frustrates an exhibit viewer more than a pushbutton that doesn’t work! _Demonstrations._ These can be informative and interesting, and you may want to include one. But since you cannot be on hand to demonstrate at all times, design your exhibit to “stand alone” without the demonstration. And when you are absent, you may avoid unsatisfied viewer curiosity either by removing the idle demonstration equipment, or by posting a “Next demonstration at ____ o’clock” sign. _Living Things._ Plants or animals which have been employed in the science project can often be displayed to lend interest and meaning to the exhibit. But since the science fair follows the project, interim growth and aging may alter living specimens so that at fair time they are considerably less meaningful or attractive than at the peak of your project. Also, if you compete in several fairs, you may find transportation and special care of your living specimens difficult and onerous. If you do plan to exhibit living specimens, familiarize yourself with local and national fair regulations governing their use, make sure that animals can be housed attractively and comfortably, and protect both animals and plants from inquisitive fingers. Then be selective and employ the minimum needed to make your point in the exhibit. About Color Properly employed, color is functional as well as aesthetically pleasing. You may find the following suggestions helpful in deciding which colors to employ in your exhibit, and where. In a space as small as your science fair exhibit, one or two basic colors, plus black and white, should suffice. Use your color in a few large blocks, not in many small patches. Different basic colors can be used to define different main areas of emphasis; then different shades of the basic colors can be used to define subareas. Life-science project exhibits can rely most safely on pastel shades running heavily to greens and yellows, while physical-science projects are portrayed frequently against more intense colors. In either case, avoid violent contrasts and “paintpot” variety. Your exhibit should convey an air of handsome restraint, not flippant prettiness or carnival gaudiness. Your colors should attract and enhance, not shock or confuse! [Illustration: Figure 8 _Far too frequently science fair judges are asked to evaluate very poor exhibits of what may have been very worthwhile science projects. Some of the more common mistakes they encounter have been included by our artist in the sketch above. Now that you have read our advice on designing science fair exhibits, how many shortcomings can you identify? (Answers below.)_