Error in Measurements: Confused?

  • Context: High School 
  • Thread starter Thread starter gladius999
  • Start date Start date
  • Tags Tags
    Errors Measurements
Click For Summary
SUMMARY

The discussion centers on the correct method for calculating measurement errors, specifically in the context of using a standard 30cm ruler and a lab burette for titrations. It is established that for a ruler, the error is determined as half the smallest division, which is 0.25mm for a 0.5mm smallest division. In contrast, when using a burette, the titre is considered as half the smallest division as well. The proper approach for averaging multiple measurements involves summing all readings and dividing by the number of measurements (n), while the uncertainty of the average is calculated by dividing the uncertainty of a single measurement by the square root of n.

PREREQUISITES
  • Understanding of measurement error concepts
  • Familiarity with standard measurement tools like rulers and burettes
  • Knowledge of averaging techniques in experimental data
  • Basic principles of random uncertainties in measurements
NEXT STEPS
  • Research the principles of measurement uncertainty in scientific experiments
  • Learn about the differences between systematic and random errors
  • Explore advanced techniques for error propagation in measurements
  • Study the use of statistical methods in analyzing experimental data
USEFUL FOR

This discussion is beneficial for students in scientific fields, laboratory technicians, and educators who need clarity on measurement error calculations and their implications in experimental results.

gladius999
Messages
60
Reaction score
0
This has been very comfusing. Is the error in taking a reading the smallest or half the smallest division? Say a standard 30cm ruler, you can judge to nearest 0.5mm but since you take 2 readings you need to double the error. But then in titrations using a lab burette you count the titre as half the smallest division? I am very confused here as I cannot decide what to put when a question in an exam asks for the error in the reading.
 
Physics news on Phys.org
For measurements of this type, where all the random uncertainties (not errors!) are equal and there are no systemantic uncertainties:
For n measurements:
Add all the measurements and divide by n to get average (don't use rms here).
Divide the uncertainty of one measurement by sqrt(n) to get the uncertainty of the average.
Bob S
 

Similar threads

  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 8 ·
Replies
8
Views
7K
  • · Replies 18 ·
Replies
18
Views
3K
  • · Replies 25 ·
Replies
25
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 18 ·
Replies
18
Views
4K
  • · Replies 15 ·
Replies
15
Views
4K