Question

carrot investigation
bag 1
bag 2
bag 3
water
water
water
isotonic solution
hypertonic solution
hypotonic solution
carrots have about 3% sodium content. a student investigated the effect of salt water on carrots. carrots
were placed in 100 ml each of three different concentrations of salt water. after one day, the carrots in
bags 1 and 3 were still crisp, while the carrots in bag 2 had become limp. what was the independent
variable in this investigation?
a. concentration of salt
b. size of the carrots
c. amount of water in the bag
d. firmness of the carrots

Explanation:

To determine the independent variable, we recall that the independent variable is the factor that is manipulated or changed in an experiment to observe its effect on the dependent variable. In this carrot investigation, the student used three different concentrations of salt water (isotonic, hypertonic, hypotonic). The concentration of salt is what was varied to see its effect on the carrots' firmness. The size of the carrots (option B) and the amount of water (option C) were likely kept constant (each bag had 100 mL of solution), so they are controlled variables. The firmness of the carrots (option D) is the dependent variable, as it is the outcome being measured (affected by the salt concentration). So the independent variable is the concentration of salt.

Answer:

A. Concentration of salt