Question

Jim is investigating the effect of the amount of salt in water on the growth of sunflower plants. He plants three sunflowers in three identical pots filled with the same type of soil. He places the pots in a sunny location. He mixes 500 milliliters (mL) of water and 15 grams (g) of salt and uses it to water one sunflower plant twice a week. He mixes 200 mL of water and 10 g of salt and uses it to water another sunflower plant twice a week. He mixes 100 mL of water and 2 g of salt and uses it to water the third sunflower plant twice a week. He measures the height of the sunflower plants each week. At the end of one month, Jim's sunflower plants are the same height. He concludes that the amount of salt in the water does not affect the growth of sunflower plants. Was Jim's experiment well-designed?
Question 1 options:

No; he changed the amount of salt he used for each plant.


No; he changed the amount of water he applied to each plant.


Yes; he observed and measured the plants for one month.


Yes; he had three trials.

Answer 1

Answer:

Option B. No; he changed the amount of water he applied to each plant.

Explanation:

The amount of water cannot be changed during the application of salt. The experiment is to check the effect of salt on the growth of sunflower plant. So he has to change only concentration of salt not amount of water. The conclusion is correct because sunflower is the most salt resistant plant which means salt concentration have no or very less affect on sunflower.