Final answer:
To study the effect of different colors of light on the rate of photosynthesis in pondweed, set up controlled experiments with tanks exposed to each color, measure the oxygen outputs as a proxy for photosynthetic activity, and potentially use a spectrophotometer to analyze pigment absorption.
Step-by-step explanation:
To investigate how the rate of photosynthesis in the pondweed is affected by different colors of light, a methodical approach would be necessary. One could set up several tanks with pondweed under controlled conditions, with each tank exposed to a specific color of light (blue, green, orange, etc.). The intensity and duration of light exposure should be consistent across all tanks.
A reliable way to measure photosynthesis in this experiment would be to count the number of oxygen bubbles produced by the pondweed, which is a byproduct of photosynthesis. This can be done over equal intervals of time for each color of light. To ensure accuracy in the results, it might also be beneficial to use a spectrophotometer to analyze the water's dissolved organic carbon (DOC) as a control for factors unrelated to light color affecting photosynthesis.
By comparing the number of bubbles produced and possibly the pigment absorption using a spectrophotometer, one can determine the relative rate of photosynthesis under each color of light. This experiment would take into account that different pigments in the pondweed might absorb different wavelengths of light more efficiently, as revealed by absorption spectra measurements.