
#1
Mar3105, 04:28 PM

P: 56

Can one read a meter stick down to a tenth of a millimeter? For example, could I reasonably measure an object as 32.43 cm using a meter stick?




#2
Mar3105, 04:33 PM

Mentor
P: 7,291

.1 mm on meter stick is gotten from a fair guess. You need to combine that fair guess with multiple measurements to obtain a statistical basis then compute an average. Your result should state a estimate at the magnitude of your error, perhaps the standard deviation of your data.




#3
Mar3105, 07:58 PM

P: 2,223

As far as significant figures go, if it is marked down to milimeters, the best measurement you can get is 0.0001m, you are allowed to guess one decimal place beyond what you can measure, provided you show a realm of error in the same magnitude.




#4
Apr105, 07:52 AM

Sci Advisor
PF Gold
P: 2,793

Meter Stick
I've used metre sticks from which pretty precise readings could be taken, but the accuracy was really poor (perhaps 2mm out over the whole length).




#5
Apr105, 08:17 AM

Emeritus
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#6
Apr105, 01:41 PM

P: 56





#7
Apr105, 03:08 PM

P: 2,223

On a meter stick, typically marking are up to milimeters.
1 millimeter = 10 ^ 3 m = 0.001 m Lets say your measuring a pencil You can measure the number of millimeters exactly without any error, right? Just count up the ticks. This value is exact, lets say its 0.104m, or 10.4cm. After that, you are permitted to estimate up to one decimal place more, for example, if its really close to the 4mm mark, you can guess it to be about 10.41cm, or 10.42cm, something like that. if its clsoe to the middle, 10.45. The point is you can put a reasonable estimate on this value. It is not reasonable however to say that a pencil is 10.42434395098cm just by looking off a ruler, because you can't obtain such a high accuracy. The most you can say is what you can observe as exact, plus one more decimal place. 


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