Precision and Accuracy in Measurements: A Tale of Four Graduated Cylinders

The concepts of precision and accuracy help students understand that uncertainty accompanies even our best scientific measurements. A model experiment can be used to distinguish the two terms. The experiment uses four graduated cylinders which give measurements of different accuracy and precision. Such terms as mean, range, standard deviation, error, and true value are defined through an illustration. The discussion leads to the conclusion that random and systematic errors are not fundamentally different. Finally, suggestions are given for introducing error analysis into the general chemistry classroom and laboratory. Our goal is to improve the student's critical thinking skills.