A manipulated variable is the independent variable in an experiment. It's called “manipulated” because it's the one you can change. In other words, you can decide ahead of time to increase it or decrease it. In an experiment you should only have one manipulated variable at a time.

What are manipulated variables?

More specifically, in an experiment, a variable can cause something to change, be the result of something that changed, or be controlled so it has no effect on anything. Variables that cause something to change are called independent variables or manipulated variables.

What is an example of a manipulated variable?

The manipulated variable in an experiment is the one variable of the experiment that the scientist decides will change. ... In the salt and water experiment, for example, the manipulated variable is the amount of salt added to the water. In the plant experiment, the manipulated variable is the light.