Problem Statements and Variables

During the next two weeks, we will be working on a big project.  We will be designing and performing an experiment involving density.  The final product will be a written lab report.  This report will be our first really big summative assessment, bigger than both of our quizzes so far combined.  It is really important that you put some effort into this and use your class time to ask questions and make sure you really understand everything.

Today, we talked about writing proper problem statements and identifying the variables in an experiment.  A problem statement is just the question we are trying to answer.  In this and in all future experiments, we will use a specific format for our problem statements:

What is the effect of 'experimental variable' on 'dependent variable'?

All of the problem statements we will ever write in this class will follow this format - only the variables will change.  We also identify each of the variables by circling the experimental variable and underlining the dependent variable.  The experimental variable is the thing we change in an experiment.  There should only be one experimental variable in an experiment - everything else should stay the same.  Recall the t-charts we made back when we talked about the requirements of science.  The experimental variable was on one side of the chart, and we listed all of our constants on the other side.  The dependent variable is the thing we measure in an experiment.  The dependent variable 'depends' on the experimental variable.  Measuring the dependent variable is how we will answer our question.  We spent most of the class period today writing problem statements in the correct format and identifying the experimental and dependent variables in each one.