what is a controlled variable
A controlled variable, also known as a controlled factor or constant variable, is a variable in a scientific experiment that is intentionally kept constant or unchanged throughout the course of the experiment. It is used to ensure that any observed changes or effects can be attributed solely to the manipulated variable, also known as the independent variable.
To understand what a controlled variable is, let's consider an example: Suppose you want to study the effect of different fertilizers on plant growth. In this case, the type and amount of fertilizer you use would be the independent variable. However, to ensure that the observed differences in plant growth are solely due to the fertilizers and not other factors, you would need to control other variables.
For instance, you might want to keep the following variables constant:
1. Light: Ensure that all plants receive the same amount and intensity of light. This could be done by placing all the plants in an identical light environment.
2. Temperature: Maintain a consistent temperature for all the plants. You can use temperature-controlled chambers or grow the plants in the same room with stable temperature conditions.
3. Watering: Provide the same amount of water to each plant at regular intervals. This can be done by carefully measuring and delivering the same volume of water to each plant.
By controlling these variables, you can isolate the effect of the fertilizer and determine its impact on plant growth without interference from other factors.
In summary, a controlled variable is a factor or condition in an experiment that is kept constant to minimize its influence on the dependent variable, allowing researchers to study the effect of the independent variable more accurately.