Working models and games
Imagine interesting science projects that actually are fun to play with. Making sparks fly from the ends of swords or getting a gentle fog to descend on the room. These are not so difficult to do when you know the science behind them. And they can become a part of your science fair project with ease.
Simple but working science projects that actually do something are always more interesting than detailed models that do nothing. That is why even something as simple as a parachute dropping an egg from a height is much more interesting than charts and reports.
So the minute you add motion to the project it captures the attention of the viewers. If you add an interactive element it will become even more popular. That is why the games at a fair are more popular than the displays. Ever notice that they have the largest crowds?
They are also more likely to catch the attention of the judges. So put on your thinking cap and come up with interesting games and working models that use science principles. Check out the Fun Aero plane that you can make here. It would be fun to fly this at the science fair.