What is a fundamental requirement for data collection in experiments?

A fundamental requirement for data collection in experiments is the use of controlled variables. Controlled variables refer to the factors that are kept constant throughout an experiment to ensure that any changes in the dependent variable are solely due to the manipulation of the independent variable. This control allows for clear cause-and-effect relationships to be identified, thereby increasing the validity and reliability of the data collected.

In experiments, if variables other than the independent variable are allowed to change, it can introduce confounding factors that skew the results. For instance, if a scientist is testing a new fertilizer on plant growth, all other conditions such as sunlight, water, type of soil, and temperature should remain constant. This ensures that any variations in plant growth can be directly attributed to the effect of the fertilizer being tested.

Utilizing controlled variables is crucial for accurately observing and measuring the outcomes of an experiment, enabling researchers to draw credible conclusions based on the data collected.