So this was the lego car we built following some detailed instructions and substituting a few parts here and there.  We were lucky enough to get a working battery.

The experiment itself was fairly straightforward.  Once the car was assembled we measured the diameter of the wheels and calculated the circumference (C=Dπ).  We then used the Labview program to set the motor power to 75 and to program the motor to run for 1 second.  One the car stopped we measured the distance it had traveled in that second.  On the first trial the distance was measured to be .25 meters by our group and .269 meters according to the computer.  We took these two numbers and calculated the percent of human error.  The average between the human measurement and the computer was .259 meters so the percent error was 7.33%.  For our next trial we set the motor speed to 50 and again measured the distance the car traveled in 1 second.  Because the motor power was lower in this trial the car did not travel as far.  The human measurement and the computer both measured the distance to be 16.5cm or .165 meters.  Therefore, the percent error on this trial was 0%. Sweet.  For the final trial we had the motor power set to 50 and allowed the motor to run for 2 seconds.  We measured the car to have traveled a distance of 33.1 cm and the computer measured a distance of 33.5 cm.  The average was .333 meters and the percent error was 1.2%.

There were a few purposes to this experiment.  One was to give the students a feel for the type of math that is used in these types of experiments.  For example the calculation of circumference and how this is important when considering RPMs.  The experiment certainly helped me to understand the relation between these concepts as I am not a math oriented person.  Also, this experiment clearly helped everyone to become more familiar with the Labview program.  How it works, the accuracy and type of data it produces, and the data that needs to be entered in order for it to work.    Furthermore, the experiment required students to acknowledge that considering the potential for human error is important in any experiment.