I am writing a prac report regarding Hooke's Law, and am uncertain how many significant figures I should write my results in in my results table. I have heard that in my prac report, I must keep my significant figures consistent, that is, all data measured by the same device should have the same number of significant figures.
My masses were pre-measured and inscribed on the weights themselves. The spring extension was measured with a centimeter ruler, and 1mm was the smallest increment.
I have data similar to this:
Mass (g)__Ave. Extension (cm) ___Uncertainty (cm)
150 _____ 11.8________________ etc.
The Attempt at a Solution
As shown above, the significant figures are inconsistent, but I'm not sure how to make them consistent. For the masses for example, I can't just add a ".0" to the end of "50" for example, to make "50.0" in order to make the number of significant figures 3, in line with the rest of the masses, as that would increase the accuracy of the measurement. Like wise with the extension, the smallest increment was 1mm, so I can't just add a "0" to "2.1" to make "2.10" for the number of significant figures to fit with "11.8" and "16.7". As for the uncertainty, I have no idea what to do with it. I was taught that uncertainty for analogue devices was plus or minus half the smallest increment. So for the ruler it would be 0.05cm. This only has one significant figure however, do I need to change this at all?
Thanks! Any help would really be appreciated!