Independent and Dependent Variables

When you are doing an experiment there are always there are two types of factors that can have an effect on your experiment: Controls and Variables.

-Controls are factors that you are keeping unchanged throughout the experiment.

-Variables are the things that will change (or vary) in your experiment. There are two types of variables: Independent variables and Dependent Variables.

- Independent variables are the factors that you are manipulating in your experiment. Your are testing their effect on something. You should try to have only one independent variable so that you know that is the variable causing the change.

- Dependent variables are quantities you are measuring to determine if there is an effect from the independent variable. You do not manipulate the dependent variable directly. You are changing the independent variable and seeing if the dependent variable changes because is "depends" on the independent variable.

-Example: Say you were testing how the mass being towed changed the ability for a certain pickup truck to accelerate. You would have several controls for all the trials: the same truck, the same road, same weather conditions, maybe even the same size and shape for the object being towed. You would vary the mass being towed under these controlled conditions, making it the independent variable. You would measure the acceleration of the truck with each of the different payloads to see if it changed, making it the dependent variable.

-Graphing: It is convention to graph the independent variable on the X axis and the dependent variable on the Y axis. I would expect that you do this in all of your lab reports unless specifically told otherwise, or unless you had a well articulated reason for going against this convention.