Question

A student sets up a controlled experiment to test the effect of a fertilizer on plant growth. Why is this not a good experimental design?

A. The second plant should also be given some fertilizer.
B. The second plant had different controls and so it cannot be compared for just the effect of fertilizer.
C. The second plant should have a change in temperature.
D. The second plant should not have that much water every day.

Answer 1

The second plant had different controls and cannot be compared for just the effect of fertilizer.

Step-by-step explanation:

The student's experiment is not a good experimental design because of option B: The second plant had different controls and so it cannot be compared for just the effect of fertilizer. In a controlled experiment, the experimental group (in this case, the corn with fertilizer) should be compared to a control group that is identical in all aspects except for the independent variable being tested.

This allows us to isolate the effects of the independent variable and determine its impact on the dependent variable (plant growth). By having different controls for the second plant, it introduces additional variables that can affect the results, making it difficult to draw accurate conclusions about the effects of the fertilizer.