Two students were testing the amount of fertilizer that would best promote the growth of tomato plants in a garden. Which of the following could be an unavoidable source of experimental error?
Select one:
a. variation of tomato plants
b. amount of water given to the plants
c. time given to the experiment
d. fertilization during the experiment
Think of it this way. Over which source would the experimenter have the least control?
a. variation of the tomato plants
All of the options presented could potentially be sources of experimental error, but the one that is most likely to be unavoidable is a. variation of tomato plants. It is difficult to control all factors that can affect plant growth, including genetic variability among tomato plants. Even if the same type of tomato seeds are used, individual plants may still exhibit slight differences in growth due to genetic factors.
To determine which of the following could be an unavoidable source of experimental error in testing the amount of fertilizer that promotes tomato plant growth, we need to understand the factors that could potentially affect the outcome of the experiment.
a. Variation of tomato plants: This factor refers to the genetic differences among tomato plants. If the students are using different varieties of tomato plants or seeds from different sources, this could introduce variability in the results. However, if the students are using the same variety of tomato plants or if they control for genetic variation by randomly assigning plants to different fertilizer treatments, this factor may not be a significant source of error.
b. Amount of water given to the plants: Water is an essential component for plant growth, and its availability can significantly impact the plant's development. If the students do not consistently provide the same amount of water to each plant or if they do not control for the moisture levels across the different experimental groups, this could influence the results. Therefore, the amount of water given to the plants holds potential as an unavoidable source of experimental error.
c. Time given to the experiment: The duration of the experiment can influence plant growth because different stages of growth require varying amounts of time. For example, if the students terminate the experiment before the plants have reached their full growth potential or if they let the experiment run for too long, it could affect the results. Therefore, the time given to the experiment could be an unavoidable source of error if not properly controlled.
d. Fertilization during the experiment: The main focus of the experiment is to test the effect of different fertilizer amounts on plant growth. If the students accidentally or intentionally apply additional fertilizer during the experiment or if they fail to apply the fertilizer according to the designated treatment groups, it could introduce bias and affect the results. Hence, fertilization during the experiment could be an unavoidable source of error if the application is not carefully controlled.
Based on the analysis, the potential unavoidable source of experimental error is:
b. Amount of water given to the plants
While the other factors mentioned could also contribute to experimental error, controlling the water supply is crucial to ensure consistent conditions for the plants and minimize variability in their growth. To minimize the potential error, the students should carefully measure and provide the same amount of water to each plant or replicate group, effectively controlling this variable as much as possible.