Teaching Photosynthesis

This school year I asked if I could participate more in classroom activities. The teachers were more than happy to give me time once or twice a week to come in and teach both morning and afternoon sessions (school days are half-days in Paraguay). The school is very small, only 57 students in all. Because deforestation is a major problem in Paraguay I have decided to start off with a series of classes on trees and reforestation. Our first class was centered around the importance of trees as well as the current problem of deforestation. The idea of this class was to nail home the importance of trees and develop a deeper appreciation for forests while the children are still young. The most recent class was centered around photosynthesis. This is a tricky subject to teach. Most people in my site don't really understand what photosynthesis is, so to try teaching it to children was a challenge. We first started talking about breathing; why do we breath? What do we breath? What is oxygen and carbon dioxide and where do they come from? From there we went into trees and plants and how they too breath just like us but instead of breathing oxygen they breath carbon dioxide.

Once the basics were established the kids easily grasped how clorophyll captured photon energy and transfered it through the electron transfer chain in the light-dependent reaction thus creating ATP and the full mechanism of the Calvin cycle (ok, not quite).

To drive home the topic we did a little art/science project. The kids did leaf rubbings (which they LOVE!) and we made a diagram of what goes into a plant/tree and what goes out. Using arrows we showed nutrients from the dirt, water from the clouds, energy from the sun, and carbon dioxide from humans going into the leaf, while an arrow leaving the leaf depicted oxygen leaving.

Whether or not all the students really understood photosynthesis is not necessary. I wanted to teach this subject not to increase their knowledge of the workings of plants but as a means for increasing their appreciation and awe in trees and other plants. Maybe that way they will be more inclined to plant more trees, or at least not cut down those that are left.