Question

I did an experiment in my chemistry lab in which the goal was to determine the density of water using mass and observed volume.

I have to report an absolute uncertainty but I am confused.

If thermometer had an absolute uncertainty of +1, had increments of 1 degree, and I measured the temp to be 19.5 because you can still estimate to the 100ths place,

can I report my data as 19.5 +/ 1 or does it have to be 20 +/ 1

Answer 1

If you're adding or subtracting quantities with uncertainties, you add the absolute uncertainties. If you're multiplying or dividing, you add the relative uncertainties. If you're multiplying by a constant factor, you multiply absolute uncertainties by the same factor, or do nothing to relative uncertainties.

So you have to submit your data as 19.5+/1, because the most perfect report is preferable and you have to submit your answer without estimation because you already has the perfect temperature value.