A responding variable, also known as a dependent variable, is a factor or condition that changes as a result of the manipulated variable in a scientific experiment. It is the effect or outcome that scientists observe for changes. The responding variable is usually named in the title of the project or experiment.

For example, in an experiment investigating how light affects plant growth, the manipulated variable would be the amount of light, while the responding variable would be the height of the plants. Another example would be an experiment investigating how drinking caffeinated beverages affects mood, where the manipulated variable would be the amount of caffeine consumed, and the responding variable would be the mood of the participants.

The responding variable can be measured, such as height, weight, or length, or it can be observed, such as emotions, color, or taste. It is important to be able to observe or measure these changes to call a variable a responding variable.

In summary, a responding variable is the factor that changes in response to the manipulated variable in a scientific experiment. It is also known as the dependent variable and is the effect or outcome that scientists observe for changes.