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The Effects of Straw Rockets

Building and flying straw rockets are a fun way for children to learn how properties of engineering affect flight patterns. Straw rockets can be constructed by wrapping a small sheet of paper around a pencil to form a tube, then removing the pencil and replacing it with a soda straw. Fold the tip of the paper tube to form the rocket's nose, and add paper fins for flair and added balance. Each component of the straw rocket has an effect on the height and distance it can fly.

Effect of Nose
- The nose of the straw rocket should be folded and pinched tightly to ensure that it is airtight. If the folds of the nose are crisp and straight, rockets center of gravity will be closer to the nose and it should fly straighter. If the straw rocket is landing continuously on its side, its nose may need more weight. A paper clip or a piece of tape can provide the small weight required to draw the center of gravity towards the rocket's nose and straighten out its trajectory.
Effect of Weight
- Discovering the ideal weight for a straw rocket can be a tricky process. If the rocket is too heavy, it won't fly very far. But if there is not enough weight on the rocket's body, then it will lack direction and the strength needed to overcome the air resistance of a launch. For this reason, regular writing paper is the recommended material for building a straw rocket. It is light enough to leave the ground, but retains its shape in a way that a lighter material such as a face tissue would not.
Effect of Launch Angle
- The straw rocket's launch angle also requires a balance between two extremes. A steep launch angle can thrust the rocket vertically but will not allow it to gain much distance, while a shallow launch angle will gain more horizontal distance but cannot fly high. A 45 degree launch angle maximizes both vertical and horizontal force, allowing the rocket to fly high and far.
Effect of Fins
- Fins, like the nose, help the straw rocket to keep its balance and fly straight. Large, bulky fins will add more weight to the rocket and slow it down, so smaller fins are preferable. Adding fins to the rocket will shift its center of pressure, which should always be behind the center of gravity. Unless the rocket has been heavily weighted on either end, its center of gravity should be in its middle; therefore, the fins should be attached towards the back of the rocket. If they are placed in the middle, the centers of gravity and pressure will be in the same spot, and the rocket will drop quickly because it does not have a clearly designated forward end. If the fins are placed at the front of the rocket, the center of pressure will be ahead of the center of gravity and the rocket will try to fly backwards.

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