Applied Data Visualization for AP Chemistry Science Fair: Phototropic and Rotational Effects on Germinating Brassica Rapa
Alan Bartels; Ben Donahue, Students, Lexington High School
The purpose of this project was to determine the optimum color of light and rotational speed to manipulate a germinating Brassica rapa plant’s growth. The effect of light on a plants growth is well documented, as well as the effect of gravity/rotational forces on plants development. However, combining the two variables, during the initial germinating stages of Brassica rapa is not. It was hypothesized that blue and white light would have the greatest phototropic effect, while increasing the rotational speed would increase the angle of deviation from vertical plant growth, along a vector perpendicular to the axis of rotation. A custom rotational apparatus was built to spin 2 towers each with 15 film canisters, each of which contained 2 Brassica rapa seeds. Each film canister had one pair of LEDs of the possible combinations of the following color LEDs: Red, White, Blue, None, Green, for a total of 15 possible permutations. After 3 days, each plant was photographed, and the angle of growth and the arc length of the plant were measured using Graphite®, a CAD program. The results suggested that rotational speed had no statistically significant effect on either angle of growth or arc length. The results also suggested that blue light had the greatest phototropic effect. A conclusion could not be made about the effect of color of light on the arc length, due to a large statistical variance. The results from this experiment could be applied in industrial greenhouse environments, where the ability to manipulate a plant’s growth could be beneficial, either due to more efficient usage of space, or simply aesthetically