What does a scientist test when using a controlled experiment?
When conducting a controlled experiment, a scientist tests the effects of a single variable or condition on the outcome of the experiment. The scientist manipulates the independent variable (the variable being tested) and keeps all other variables constant or controlled. By doing so, the scientist can determine if any changes or differences in the outcome of the experiment are solely due to the manipulated variable.
When a scientist conducts a controlled experiment, they test the effects of a particular variable on the outcome of an experiment. The variable being tested is known as the independent variable. However, to ensure that the experiment is reliable and valid, the scientist also includes a controlled group and a control group.
1. Independent Variable: This is the variable that the scientist intentionally changes or manipulates during the experiment. It is the factor being tested, and its effects are observed and measured. For example, if the scientist wants to study the effects of different fertilizers on plant growth, the type or concentration of fertilizer would be the independent variable.
2. Controlled Group: The controlled group or control group serves as the baseline against which the effects of the independent variable are compared. The controlled group remains unchanged and does not receive any manipulation or treatment. This helps to isolate the effects of the independent variable and evaluate its impact accurately.
3. Dependent Variable: The dependent variable is the outcome or result that is measured or observed based on the changes made to the independent variable. It is the variable that the scientist expects to be influenced by the independent variable. In the fertilizer example, the dependent variable could be the height or mass of the plants.
By testing the effects of the independent variable while keeping other factors controlled or constant, scientists can determine whether the changes in the independent variable truly cause the observed changes in the dependent variable. This controlled approach helps establish cause-and-effect relationships between variables.