03.04.2016
Written By: Becca Mackenzie
Piggy-backing off of what the students learned about light last session, we had the students design experiments to test the effect different colored lights have on plant growth. We provided red, green, blue, yellow, cyan, and magenta filters along with a large polarizer. They were asked to come up with a research question, for example, is green light or red light better for plant growth? Each group got fifteen radish seeds (a quick-growing plant), soil, and growth pods and together, they decided how to distribute their plants among the different light conditions. We encouraged the students to have replicates and a control, but for the most part, we wanted them to be in charge of the experiment.
To jog their memories about what they had learned previously, we had the color transparencies (new ones, which work way better than our old ones), the colored flashlights, and the solar cell. I was pleased and impressed with how much they remembered and how they used their previous findings to guide their experimental design for the plants.
After planting their seeds and assigning the light condition, we asked the students how they were going to measure growth. Some of the response variables they suggested were height, number of leaves, and thickness of leaves. So over the next two weeks, the students are going to track the growth of their plants and then we’ll return to help them analyze and present their data.
I really like this experiment because, although it may not be as exciting as some of our other experiments, it allows the students to design an experiment, record data over a longer period of time, and then present their findings.