Question

Controlled experiments often take place in laboratories or indoor settings where environmental can be controlled. In a controlled experiment, the scientist is exploring the relationship between two variables, the independent variable, or the one being changed or manipulated and the results of that, the dependent variable. All other variables must be controlled or kept constant. This means, that in a controlled experiment, only the ONE thing being investigated can be changed. Everything else must be kept the same to ensure the cause of the change. Which of these contains ALL of the components of a controlled experiment?

Answer 1

A controlled experiment requires careful manipulation of an independent variable and measurement of a dependent variable while holding other variables constant. This structure allows for the determination of cause-and-effect relationships between variables.

Step-by-step explanation:

A controlled experiment is an important type of scientific investigation that is carried out under carefully regulated conditions. This experiment type is designed to test the causal relationship between an independent variable (the variable that is manipulated or varied by the researcher) and a dependent variable (the variable that is measured to see the effects of the independent variable).

To conduct a valid controlled experiment, all other variables, called control variables, must be held constant to ensure that any observed changes in the dependent variable are due solely to the manipulation of the independent variable. Uncontrolled variables could otherwise introduce bias or noise, potentially leading to incorrect conclusions. Therefore, to answer the original question, a controlled experiment must consist of at least one manipulated independent variable, a measured dependent variable, consistent control variables, and often includes a control group that does not receive the experimental manipulation.

In some experiments, like the phosphate and algae growth hypothesis mentioned in the provided information, the experimental variable is the presence or absence of a nutrient, with controlled variables including the volume of water in each tank to ensure consistent conditions. This approach allows researchers to measure changes in the dependent variable confidently and ensure that the experiment testifies to the relationship between the two key variables.