The largest source of error, however, stems from the amount of baking soda used. Due to two of the three students not having access to a digital mass balance, the student with the mass balance measured the mass of baking soda in one standard teaspoon as 4.5g. Thus, a teaspoon was used to measure baking soda during each trial by all students for consistency. Previous studies on household measuring instruments have cited the glassware as having varied accuracy even between repeat measures with the same instrument. Therefore, because of this possible mass error and the error associated with the accuracy of other at-home titration instruments, this titration may be subjected to a certain degree of uncertainty.