Final answer:
The proposed experiment to measure the effect of light color on the rate of photosynthesis using the Winkler method is well-founded. Care should be taken to not expose samples to air and utilize LEDs for controlled light exposure. Additionally, there is an upper limit on light intensity beyond which photoinhibition can impair photosynthesis.
Step-by-step explanation:
The idea to investigate how the color of light affects the rate of photosynthesis using an Elodea plant and the Winkler method to measure dissolved oxygen is a sound experimental design.
It allows for quantification of the photosynthesis rate under different light conditions by measuring the mg/L of dissolved oxygen in the water. For accuracy, use LEDs of specific wavelengths for consistent light colors, and ensure the Winkler method samples are not exposed to the atmosphere while handling.
Regarding the plants' growth under different colored light, based on chlorophyll a and b absorption spectra, plants grown under blue light would likely show the most growth, followed by those under orange light, with green light resulting in the least growth. This is because chlorophylls absorb light primarily in the blue and red regions, with green being reflected, not absorbed.
In terms of light intensity, it is important to consider that there is indeed an upper limit. Excessively intense light can lead to photoinhibition, where the photosynthetic apparatus can be damaged, slowing down or even halting photosynthesis, which in turn would negatively affect algal growth.