Scientific Method And Identifying Variables

The dependent variable in this experiment is the amount of stain left after washing. This is because the purpose of the experiment is to determine which detergent removes chocolate stains best, and the amount of stain left after washing is the measure of effectiveness for each detergent. The other options - time of washing, temperature of water, and Tide - are all independent variables that can be manipulated in the experiment.

The controlled variables in this experiment are the time of washing and the temperature of water. These variables are controlled by the experimenter and kept constant throughout the experiment. By washing the clothes for 20 minutes and using lukewarm water, the experimenter ensures that these variables do not influence the results. The amount of stain left after washing is the dependent variable, as it is the outcome that is being measured and compared between the different detergents. Tide is not a controlled variable but rather one of the detergents being tested.

The independent variable in this experiment is the type of detergent used - Surf, Tide, and Ariel. The experiment is testing which detergent removes chocolate stains best, so the researcher is manipulating the independent variable by using different detergents. The dependent variable would be the effectiveness of stain removal, which is not mentioned in the question.