How to write uncertainities on different measurement

  • Thread starter Awsom Guy
  • Start date
  • Tags
    Measurement
In summary, when writing uncertainties for different measurements, it is important to round the uncertainty to one significant digit and round the measurement result to the same amount of digits in the same units. For analogue equipment, the uncertainty is half the smallest measurement possible, while for digital equipment it is the smallest measurement possible.
  • #1
Awsom Guy
77
0
I need some advice on how to write uncertainities on different measurements.
I need this urgently.
Thanks:cool:
 
Physics news on Phys.org
  • #2


with a delta [tex]x \pm \Delta x[/tex]
 
  • #3


i mean on measurements
 
  • #4


[tex]x = (3.01 \pm 0.01) \text{ cm}[/tex]

You mean like that? Otherwise, your question is so vague and general, I have no idea what you want.
 
  • #5


Nick89 said:
[tex]x = (3.01 \pm 0.01) \text{ cm}[/tex]

You mean like that? Otherwise, your question is so vague and general, I have no idea what you want.


That is it exactly what I want.
 
  • #6


Well, what is your question about it?

You simply write down the result of your measurement, and then you decide what the uncertainty is. You round the uncertainty to one significant digit (0.0193 becomes 0.02) and you round the measurement result to the same amount of digits (as long as they are in the same units). You then write it down as
[tex]y = (x \pm \Delta x) \text{ [unit]}[/tex]
where x is the measurement result and delta x the uncertainty.
 
  • #7


Well my question was about the measurements in a ruler in mm and a protractor.
I guess it would be +/-1 degree and +/- 0.5mm.
Thanks for your help anyway.
 
  • #8


Hi there,

I believe I can help you with this one. The uncertainty of an analogue equipment is half the smallest measurement possible (0.5mm for your ruler). The uncertainty of a digital device is the smallest measurement possible (1mm for digital ruler that measures in mm).

Cheers
 

1. How do I determine the uncertainty of a measurement?

The uncertainty of a measurement is determined by evaluating the precision and accuracy of the measurement. This involves taking multiple measurements and calculating the average, as well as considering any potential sources of error. The uncertainty is typically expressed as a range of values, such as ±0.5 cm.

2. What is the difference between random and systematic uncertainties?

Random uncertainties arise from the inherent limitations of the measurement tool or technique, and can be reduced by taking multiple measurements. Systematic uncertainties are caused by a consistent error or bias in the measurement process and are more difficult to identify and correct for.

3. How do I write the uncertainty for a simple measurement, like length or mass?

The uncertainty for a simple measurement can be written as the measurement value ± the estimated uncertainty. For example, if a length measurement is 20 cm with an uncertainty of ±0.2 cm, it would be written as 20 ± 0.2 cm.

4. Do all measurements require uncertainty values?

No, not all measurements require uncertainty values. Some measurements may have such a small uncertainty that it is not significant, while others may have a known and accepted uncertainty value. It is important to consider the purpose and context of the measurement in determining if an uncertainty value is necessary.

5. How do I calculate the uncertainty for a derived measurement?

The uncertainty for a derived measurement, such as velocity or density, can be calculated using the rules of uncertainty propagation. This involves determining the uncertainties of the individual measurements used to calculate the derived measurement and combining them using mathematical operations. It is important to consider the type of uncertainties (random or systematic) and how they may affect the final result.

Similar threads

Applied I need some textbooks about Mathematical models please
    • Science and Math Textbooks
Replies
7
Views
1K
I What can we scientifically measure directly?
    • Other Physics Topics
Replies
27
Views
2K
I How was electronics propagation delay measured historically?
    • Other Physics Topics
Replies
11
Views
1K
A Photon Bouncing during APD Dead Time in Autocorrelation Measurement
    • Other Physics Topics
Replies
1
Views
633
I Thermal Interpretation and Consistent Histories
    • Quantum Interpretations and Foundations
Replies
2
Views
743
I Significant figures and uncertainty in measurements
    • Other Physics Topics
Replies
13
Views
3K
I Can you practically measure an infinite amount of some quantity?
    • Other Physics Topics
Replies
10
Views
1K
I Can anything be measured with a single measurement?
    • Other Physics Topics
Replies
26
Views
13K
B No vacuum anywhere vs the measurement of "c"
    • Other Physics Topics
2
Replies
50
Views
3K
I Lux-meter, candelas or lux, measuring nits in practice
    • Other Physics Topics
Replies
2
Views
3K

Hot Threads

Recent Insights

Back
Top