Sig Figs query for a steady flow pipe

In summary, the student is struggling with determining the correct number of significant figures to display on a data table for an experiment investigating the Reynolds number. They are unsure if they should use the lowest number of significant figures in their calculations or round to two significant figures for the final result. They are also unsure about the proper treatment of uncertainties and how to report values in their lab report.
  • #1
shortbread
1
0

Homework Statement



First let me say I'm new to lab reports at Uni, and I'm dreadful at them...

I'm having issues with how many sig figs to correctly display on a data table for an experiment I've done to investigate the Reynolds number. One particular step is to find Δp at different stages on a manometer using the equation Δp=(ρwater-ρatm)gΔ(Zw) with Zw being the difference between the left and right hand side of the manometer. all my Zw values are in mm; for example one of them is 33mm, using the equation for that particular value I get 323 Pa, I've looked around and it seems that the value I should display on the table is 320 Pa as the value I obtained should have the same SF as the lowest SF of the value used to calculate it. This seems ok for lower values but looks wrong at higher values because it feels like I'm rounding up and down a lot of the value. I would be thankful if someone could tell me if I'm going wrong and the correct procedure when dealing with SFs from measurements taken in experiments.

Homework Equations



-

The Attempt at a Solution



-
 
Physics news on Phys.org
  • #2
What do you mean with higher values?
Rounding to two significant figures is fine for a final result. It is not a proper treatment of uncertainties anyway...
 
  • #3
Don't mistake reported values for those used in calculations. Your report should contain rounded numbers, but you should never used these rounded values in your calculations. Use either full precision as spit out by your calculator, or at least use so called guard digits - that is, use several digits more than you are reporting.
 

Related to Sig Figs query for a steady flow pipe

What are significant figures (sig figs) and why are they important in a steady flow pipe?

Significant figures, also known as sig figs, are a way to express the precision of a measurement. In a steady flow pipe, sig figs are important because they help ensure the accuracy of the measurements taken and the calculations made. They also help us avoid misleading or incorrect results.

How do you determine the number of sig figs in a measurement for a steady flow pipe?

The number of sig figs in a measurement for a steady flow pipe is determined by the precision of the measuring instrument. For example, if a ruler has markings up to the nearest millimeter, then the measurement can only have one sig fig. However, if a digital caliper is used with a precision of 0.001 mm, then the measurement can have up to four sig figs.

What is the rule for rounding sig figs in calculations for a steady flow pipe?

The general rule for rounding sig figs in calculations for a steady flow pipe is to round the final answer to the same number of sig figs as the measurement with the least number of sig figs. For example, if one measurement has two sig figs and another has three sig figs, the final answer should be rounded to two sig figs.

Can you have more sig figs in your final answer than in your initial measurements for a steady flow pipe?

No, you cannot have more sig figs in your final answer than in your initial measurements for a steady flow pipe. This is because the number of sig figs in the final answer is limited by the precision of the least precise measurement used in the calculation.

What are some common sources of error when using sig figs in steady flow pipe calculations?

Some common sources of error when using sig figs in steady flow pipe calculations include using an inappropriate number of sig figs, rounding incorrectly, and using measurements with varying levels of precision. It is important to carefully consider the precision of each measurement and follow the appropriate rules for rounding to minimize error.

Similar threads

Replies
31
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
4
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
5
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
3K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
3K
  • Advanced Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
938
  • Introductory Physics Homework Help
Replies
1
Views
1K
Replies
2
Views
2K
  • Mechanics
Replies
6
Views
5K
Back
Top