At which lamp distance is photosynthesis occurring at the fastest rate?

Three students are investigating the effect of light intensity on photosynthesis by the aquatic plant Elodea. They varied the light intensity by placing a lamp at five different distances from the aquarium. The students left the room lights on and the window shades up. Then they measured how much oxygen gas the plant produced per hour at the different lamp distances. Here is their data table. a. Use the data to make a graph. b. At which lamp distance(s) is photosynthesis occurring at the fastest rate? At which lamp distance(s) is photosynthesis occurring at the slowest rate? c. The students designed the experiment to test this hypothesis: the closer the lamp, the faster photosynthesis will occur. Do their results support their hypothesis? Why or why not? d. Can you suggest a possible reason for the results being the same at 60 and 75 cm? Does this suggest any new questions to investigate? Explain.


a. Make your own graph. b. Photosynthesis occurs the fastest at the 15cm distance and falls to that produced by the ambient lighting as the distance approaches 60cm. c. Yes. The oxygen produced by photosynthesis is shown to decrease as the light source is moved farther away. d. Beyond 60cm the light source does not strengthen the ambient lighting enough to have an effect on the rate of photosynthesis.


with light I dont think there are any trick questions...twice the distance, 1/4 the closest is the best unless its burning the leaves