Phyllotaxis tool : A didactical tool for practical laboratory

Our poster presents a practical tool we have developed, which shows the divergence angle between two consecutive leaves on a plant stem. We used this tool in practical laboratory, with the purpose to explain "how much" and "what" mathematics is hidden in plants. We employed the sunflower plant as the subject for this educational activity. To make the term “divergence angle” understandable to everyone, we have reproduced a simple model of the arrangement of sunflower’s leaves. The leaves on the stem grow one per node, each at a constant divergence angle of 144 degrees from the previous, and they arrange with an evident spiral phyllotaxis. This tool allows to visualize and to evaluate the divergence angle. We obtain this angle through the reflection of the helix that wraps on the stem on the basal plane of the tool. At the end of the laboratory, participants can design the angle and measure it. The educational activity has been developed for students of primary school and for first class of secondary schools. We have also tried the event with generic public, from the age of nine up. This homemade object is low-cost and easy to realize. Idea and design developed in collaboration with Museo Civico Explorazione Treviglio (BG).