Final answer:
In a water filtration experiment, the dependent variable is the quality of water which is measured through indicators such as contaminant levels or turbidity. It changes as a result of different filtration materials or methods applied (the independent variable). Control variables are kept constant to confirm causality.
Step-by-step explanation:
The dependent variable in a water filtration experiment is typically the quality of the water after it has been filtered. This quality could be measured by several indicators, such as the concentration of contaminants, the turbidity (clarity) of the water, or the levels of specific chemicals or microbes. The dependent variable is the one that changes as a result of manipulations to the independent variable. In this case, the independent variable could be different filtration materials or methods used to treat the water.
To measure the dependent variable, you would need to take water samples after filtration and analyze them using appropriate laboratory techniques. For example, if measuring for clarity, you might use a turbidimeter or assess color visually against a standard chart. If checking for contaminants, you would use chemical tests specific to the substances of concern.
Control variables are other factors that you keep constant to ensure that any changes to the dependent variable are indeed due to the independent variable. They are important because they help to establish the causality in your experiment, confirming that it is the independent variable that is causing the change in the dependent variable.