Variables

Independent variables are variables that you change for the experiment. Dependent variables are variables that depend on the independent variables. Controlled variables are variables that you need to control throughout the experiment in order to have an accurate experiment. If you don't have an independent variable, then you don't have an experiment at all. If you don't have a dependent variable, then you don't have any data to record and compare, therefore defeating the purpose of the experiment. If you don't control your variables, then more than one variable might be affecting the outcome of your experiment, making it less accurate. You should do multiple trials to ensure a valid experiment just in case you have an outlier or something goes wrong during the experiment (just to be as accurate throughout the experiment as you can)