3 replies to this topic

[UncleJohnny]

In my investigation I have gathered this list of possible uncertainties. I'm unsure of how to combine them as
I don't have a techer at the moment and can't find my notes, help. Im doing the viscosity of water...

Scale Reading uncertainties:
Vernier Scale= 5 x10-5m
10 cm3 Measuring cylinder = 5x10-8 m3
25cm3 Measuring Cylinder= 2.5x10-7 m3
Stopwatch= 0.05s
metre stick= 5x10-3m

Random U= 2.42 x10-8

I just can't remember how to do it .

[Michael]

You make them into percentage uncertainties and the highest is the one you write down as a combination of them all.

[ad absurdum]

I thought you would express them as percentage errors and add them vectorially (i.e. you will have to find where the letters represent the magnitude of your percentage errors.). I'm not totally sure either though.

[waitingforan_alibi]

both sort of right-
if one (percentage) uncertainty is more than 3 times any other then it is the dominant uncertainty
otherwise do what ad absurdium said, although the word vectorially is WRONG! sorry, but it is!