Patrick Henry High School | IT IS MASSIVE!

Three students look at steel wool burn.Patrick Henry chemistry students conducted a series of minilabs in order to prove the Law of Conservation of Mass.  Students worked through five experiments, measuring the mass of the reactants and the mass of the products.

For each experiment, they had to determine if the mass would increase, decrease, or stay the same.  They also had to determine a source of error for each experiment, including how the error affected their results. For two of the experiments, the mass did not stay the same.  When students burned steel wool, the mass increases due to the redox reaction of the iron in the steel wool and the oxygen in the air resulting in an iron oxide compound.  When students dissolved an antacid tablet in water, the mass decreases due to carbon dioxide formation and release from the solution. Error analysis is a difficult thing for most students.  This exercise is their first step towards understanding discrepancies between expectations and results.

Contact Person: 
Cindy Woosley