I've had this question for a while now. I mean, do real scientists use significant figures? Or is it just something you learn in high school, but really never use? I feel like every time I use sig figs in a calculation and have to round off in the end, I make the results way less precise. For example (please correct me if I'm wrong), If you need to convert 4.0 oz of steroid ointment to grams, I would normally write, 113.398093 grams. However, with the sig fig rules, I am supposed to round off to make the final answer have the same number of sig figs as the measurement with the fewest sig figs, which would make my answer 110 grams. Wouldn't that make my answer A LOT less precise??? Please answer!!!
-
Yes, but they aren't used as often enough. Its really about being honest. If you measured 4.0 oz that means that the device used to measure ounces was marked off in 1 oz increments and the 10ths of an ounce were estimated.
The answer to a calculation cannot be more precise than the measurements used to make that calculation. 110 grams is correct. If you say 113.398093 grams what you are saying is that you measured the ounces using a device that had increments of 0.00001 oz. Since you were given the ounces to 2 sig figs clearly the method of measurement was not that precise. Adding the extra digits is meaningless as those extra digits no significance in reality.
The answer to a calculation cannot be more precise than the measurements used to make that calculation. 110 grams is correct. If you say 113.398093 grams what you are saying is that you measured the ounces using a device that had increments of 0.00001 oz. Since you were given the ounces to 2 sig figs clearly the method of measurement was not that precise. Adding the extra digits is meaningless as those extra digits no significance in reality.
-
I would have to agree that rounding 113.398093 grams to 110 grams would not be good scientific practice as this could cause a significant molarity difference. However, writing 113.398093 grams is not practical either. The analytical balances used in any modern research lab are only so precise. 113.4 grams would most likely be adequate for any research using that large of quantity.
-
It would actually make it more accurate because 4.0 is most likely an estimate, and since it has the least amount of sig figs, you want your answer to be precise to that measurement.
-
it's only a lot less precise when you are dealing w/ extreme multiples of the value.
if so, chances are you would be uisng metric from the start, like most of the rest of the scientific community.
if so, chances are you would be uisng metric from the start, like most of the rest of the scientific community.
-
Significant figures really used in precious instruments.