Question

Which of the following describes variables that stay the same in an experiment? A) dependent variables B) independent variables C) constants D) controls

Short answer

C) constants

Step-by-step solution

Identifying the Purpose of Each Term

To solve this problem, we need to understand what each option represents in the context of an experiment. Dependent variables are the outcomes that researchers measure in an experiment. They depend on changes in other variables. Independent variables are the factors that researchers change to see how it affects the dependent variables. Constants are factors that do not change throughout the experiment period. They stay the same to ensure the validity of results. Controls are standard groups or conditions used for comparison to determine the effect of the independent variable.

Determining Which Term Fits the Description

The problem asks which term describes variables that "stay the same" in an experiment. From Step 1, we identified that constants are variables that do not change. They remain the same throughout the experiment to provide consistent data.

Key concepts

Constants

In scientific experiments, constants are crucial for ensuring that the results are reliable and valid. Think of constants as the backbone of an experiment—they remain unchanged and provide stability. When scientists conduct an experiment, they aim to isolate the effect of one variable. To do this, they keep other factors identical.
Keeping factors constant means researchers can focus solely on how the independent variable affects the dependent variable. Constants help avoid confounding variables, ensuring that any change observed is due to the controlled experiment.
This way, anything outside the experimental focus doesn’t skew the results or add unnecessary uncertainty.

• Example: If you're testing the effect of sunlight on plant growth, constants could include the type of plant, soil, and amount of water each plant receives.

Independent Variables

Independent variables are the heart of experimental manipulation. They are the elements deliberately changed to observe the effect on the dependent variable. The independent variable is what you "mess with" to see if it causes any change.
This testing allows us to understand cause-and-effect relationships within the environment being studied. Researchers should only change one independent variable at a time to ensure clarity regarding what is causing an effect.
By doing so, they can determine which independent variable influences what.

• Example: In an experiment to see how different temperatures affect the solubility of a substance, the temperature would be the independent variable.

Dependent Variables

Dependent variables are what researchers measure during experiments. This measurement shows the outcome or effect of altering the independent variable. Think of them as the results you are interested in studying.
By closely monitoring the dependent variables, researchers can assess whether changes in the independent variable have the intended impact.

• Example: In the previous temperature experiment, the amount of substance that dissolves at different temperatures represents the dependent variable.

These measured outcomes provide the essential data used to draw conclusions about the hypothesis tested.

Controls

Controls are essential for comparing how the independent variable influences the outcome. They act as a benchmark, providing a standard point of reference. Controls help determine the real effect of the independent variables by showing what would happen if those variables were not altered.
Think of them as the "normal" conditions within the experiment—a baseline against which all other outcomes are measured.

• Example: In a medical study testing a new drug, the control group might receive a placebo to compare the drug's effects against no treatment.

Employing controls ensures that any observed changes are indeed due to the independent variable and not other external pressures or random chance.