A scientist studying the effects of gamma rays on marigolds gathered the data shown below.
Hypothesis: Marigolds exposed to higher levels of radiation will not grow as well as marigolds that are exposed to less radiation
Plant A: Gamma Rays (Rad/day) is 5. Water (mL/week) 50. Sunlight (hours/day) 0. Height (cm) 4.
Plant B: Gamma Rays (Rad/day) is 10. Water (mL/week) 50. Sunlight (hours/day) 2. Height (cm) 7.
Plant C: Gamma Rays (Rad/day) is 15. Water (mL/week) 50. Sunlight (hours/day) 5. Height (cm) 10.
The scientist came to the conclusion that the hypothesis was incorrect. Why is the scientist's conclusion flawed?
A. The scientist's conclusion is flawed because the height of the plants changed and, therefore, the experiment is not controlled.
B. The scientist's conclusion is flawed because the amount of gamma rays changed and, therefore, the experiment is not controlled.
C. The scientist's conclusion is flawed because the number of hours of sunlight changed and, therefore, the experiment is not controlled.
D. The scientist's conclusion is flawed because the amount of water was not changed and, therefore, the experiment is not controlled.
Is it C?
yes
No, the correct answer is A. The scientist's conclusion is flawed because the height of the plants changed and, therefore, the experiment is not controlled.
In a controlled experiment, all variables except the one being tested (in this case, the effect of gamma rays on marigolds) should be kept constant. However, in this experiment, the height of the plants varied across different conditions of gamma ray exposure. This means that there could be other factors influencing the growth of the plants, such as soil conditions, nutrients, or genetics, that are not accounted for and could potentially affect the results.
To have a controlled experiment, all other variables, including sunlight, water, and other growth conditions, should be kept constant across the different levels of gamma ray exposure. This way, any differences observed in the growth of the plants can be more confidently attributed to the effects of gamma rays.