In the following data table of an experiment carried out at 4°C (39.2 F) over 4 hours
Solution in bag
Solution outside bag
Bag mass change (g):
water
Water
-0.2
20% sucrose
Water
+2.4
, 40% sucrose
Water
+4.3
, 60% sucrose
water
+5.8
Which of the following options represents the dependent variable?
A.
Duration
B.
Temperature
C.
Bag mass change
D.
Sucrose concentrations.
The Correct answer and Explanation is:
The correct answer is C. Bag mass change.
In an experiment, the dependent variable is the outcome that is measured to assess the effect of the independent variable(s). In this case, the independent variables include the sucrose concentrations of the solutions inside the bags. The experiment investigates how different concentrations of sucrose influence the mass change of the bags, which contains solutions that either gain or lose mass based on the movement of water through the semipermeable bags.
Here’s a breakdown of the context:
- Independent Variables: The sucrose concentrations (20%, 40%, and 60%) are varied intentionally to observe their effects on the outcome. By changing the concentration of sucrose, the researchers can assess how it affects the mass change of the bag due to osmotic processes.
- Dependent Variable: The bag mass change is what the researchers measure to see the effects of those varying sucrose concentrations. The mass change indicates the net movement of water in or out of the bag, driven by osmotic gradients.
- Controlled Variables: Factors such as temperature (4°C) and the duration of the experiment (4 hours) are controlled to ensure that they do not influence the results. These variables remain constant to isolate the effects of the sucrose concentrations.
Understanding the relationship between dependent and independent variables is crucial in scientific experimentation. The dependent variable reflects how well the experimental hypothesis is supported. In this scenario, measuring the bag mass change allows the researchers to infer how sucrose concentration influences osmotic pressure, highlighting the importance of water movement in biological systems. By analyzing these mass changes, researchers can draw conclusions about the behavior of solutions in different osmotic environments, which has practical implications in fields such as biology and medicine.