Significant Figures

Chemistry is the study of matter, made possible through lab practices that employ precision and accuracy.  This interplay is seen most clearly in the application of significant figures. 

Photo courtesy of: Teacherspayteachers.com

Given a set of rules and examples, most students are able to appropriately apply them to measurements made in the chemistry classroom.  However, this ability quickly becomes shaky when students are required to (1) express quantitative data in appropriate Sig Figs without referencing a "rules sheet" or (2) apply existing Sig Fig knowledge to calculations. 

In exploring the causality of this relationship, I've found that students fail to integrate the reasoning of this system into their working processes. The educational goal, therefore, becomes a transformation from rote memorization to integrated understanding.  If students can invest their critical minds in the process of differentiating numbers that represent exact measurement from those that are estimated, they can begin to grasp the need for standardized expression of them.

The question then becomes, how do we build confidence in the use of Sig Fig rules and foster students' ability to extrapolate those rules to calculations?  The answer comes in the form of a familiar and under-utilized tool, the graphing calculator.  This technology would remove the need for pre-written question and answer sets which are inherently limited in application as well as subject to human error.  Informal and formal assessments would also be transformed, as students could move beyond the "right answer" into explanations of why it is such. 

Photo courtesy of: commerce.hpcalc.org