Significant Figures with Experimental Values

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Homework Help Overview

The discussion revolves around the appropriate use of significant figures in reporting experimental values. Participants are considering how to choose a number that aligns with a set of experimental measurements, specifically focusing on the implications of trailing zeros and the accuracy of measurement equipment.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the significance of trailing zeros in the context of significant figures and question the accuracy of their measuring equipment. There is a discussion about whether to report values with three significant figures or to adhere to a lesser degree of precision based on the equipment used.

Discussion Status

The conversation is ongoing, with various perspectives on how to interpret the significant figures in relation to the experimental values. Some participants suggest that the choice of number should reflect the precision of the measurements, while others express concerns about the consistency of the reported values.

Contextual Notes

There is uncertainty regarding the source of the experimental values and whether they were recorded by the original poster or someone else. Participants also note the potential for discrepancies in the measurements, indicating a need for careful consideration of the equipment's accuracy.

i_love_science
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Homework Statement
I have a group of experimental numbers: 0.320, 0.910, 0.030, 0.070, and 0.080. I have to add another number to this group, which is also an experimental value. Which one should I use: 0.738, 0.740, or 0.74?
Relevant Equations
sigfigs
I was thinking of choosing 0.740, because it looks the most consistent with the other numbers because they all have a trailing zero. But then, in accordance with sig figs, 0.74 is the right answer. Which one should I choose?
Thank you so much!
 
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It depends upon the measurement . If the previous numbers are appropriately reported on the same apparatus, then 3 sig fig is still appropriate. But I don't know which value.
 
i_love_science said:
in accordance with sig figs, 0.74 is the right answer
No, it is the right answer only if you declare that your equipment only produces that degree of accuracy. If you know that it produces 3 significant digits then a trailing 0 is a significant digit.
 
Did you obtain all of these readings, or did someone else record the existing ones? It is very suspicious that they all have a trailing zero - unless there is some inherent discreteness in the exact values.

Each value should be recorded with the precision it merits. If you are confident your new reading is between 0.7375 and 0.7385 then record it as 0.738.
 
i_love_science said:
I have a group of experimental numbers: 0.320, 0.910, 0.030, 0.070, and 0.080. I have to add another number to this group, which is also an experimental value. Which one should I use: 0.738, 0.740, or 0.74?
I know this is a semi-old thread, but hopefully the answer was that you should re-do the experiment. That's a terrible spread of measured values. Look for loose screws or something in your measuring apparatus... :wink:
 
berkeman said:
I know this is a semi-old thread, but hopefully the answer was that you should re-do the experiment. That's a terrible spread of measured values. Look for loose screws or something in your measuring apparatus... :wink:
They are not necessarily readings of the same underlying value. Maybe points on a graph.
 
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