Question

Scientists tested the effect of a fertilizer on the growth of plants. They had 2 sets of plants, Group A which gets fertilizer, water and sun and Group B which gets only water and sun (but in equal amounts to Group A).

1. Explain how this scenario is a controlled experiment and identify the manipulated variable.



2. If the scientists only performed 1 experiment but it supported their hypothesis, why can it not be considered a theory?



3. The graph below was created showing the growth of the plant. How would you know that the y-axis is measuring the growth of the plant?

Answer 1

1.) Its a controlled experiment because both groups A and B get the equal mount of sunlight and water. The manipulated variable would be the fertilizer.

2.) Because a theory must consists of more than experiment before it can actually be considered a theory. It must be performed multiple times.

3.) Because if the growth was on the B spot, the graph would be a bar graph because the growth would still increase by each day.