Keep as many controls as possible in your experiments by using the same thickness of paper for every airplane. Gather 20 sheets of legal size paper and 20 sheets of letter size paper. You will be constructing and throwing 40 paper airplanes and recording the results of each throw. Form a hypothesis on whether you think long, short, heavy or light planes will fly better, as well as those with or without wing tips.
The controls of the experiment are the length and thickness of the paper, and the design of airplane. Your letter-sized sheets of paper should be the same thickness as your legal-sized sheets of paper. Only use fresh, crisp paper. There should be no wrinkles or folds in it, and it should not be damp with humidity. Run your experiments in an air-conditioned room, away from the vents so there is no breeze to knock your airplanes off course.
Make two designs of airplane, one with wing tips and the other without wing tips. From your 20 sheets of legal-sized paper, make 10 of each design. Do the same with your letter-sized paper. The legal-sized airplanes should be longer than the letter-sized planes. Put a paperclip on the tail, or on the bottom-center of five wing tip short planes, five non-wing tip short planes, five wing tip long planes, and five non-wing tip long planes. Number all of your planes 1 through 40, keeping the same types of planes concentrically with each other. For example; number the letter-sized wing tip planes 1 through 5, the letter-sized non-wing tip planes 6 through 10, and so on according to your organizational preference.
Beginning from the same point every time, throw all your paper airplanes. Throw them the same way every time, so the throw remains a control and does not become a variable. Measure the distance of every airplane from the start. Repeat the experiment four more times, to make a total of five throws each for all 40 planes.
Make a chart of the distance for each plane for each throw. Notice which planes flew the farthest and which planes did not go far. Did any specific planes stand out as flying quite far or not far enough? Were there types of planes that tended to fly farther or less far as a group in general? Was your hypothesis correct? Address any discrepancies and report the possible reasons. Were your folds precise? Did you throw poorly? Record this information and display it in legible charts that make your conclusions clear.