Types of Variables:
Independent variables
Dependent variables
Controlled variables
Facts:
1. A variable is part of an experiment that can change, such as amount of light, or plant growth.
2. In an experiment, an independent variable either changes on its own, or you purposely change it. For example, the amount of sunlight changes during the day. You can also change the amount of light for an experiment by turning on a light for a measured amount of time or by placing the testing materials in sunlight for a measured amount of time.
3. Changes in the independent variable cause changes in a dependent variable. In other words, changes in the independent variable is the cause and changes in the dependent variable is the effect.
4. A science problem expressing an independent and dependent variable might be:
How does the amount of light affect plant growth?
independent variable: amount of light
dependent variable: growth of plant
5. Controlled variables are variables other than the independent and dependent variables. Changes in these variable could affect your results. So, these variables are controlled, meaning you want to eliminate them or control them so that they do not change. For example, the type of plant used, temperature, amount of water, etc…needs to be the same for every plant tested. Some variable are difficult to control, but you should try to make every effort to keep them the same during the testing.