Temperature Measurement: Are All Thermometers Created Equal?

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Discussion Overview

The discussion revolves around the differences in temperature readings obtained from various types of thermometers when measuring the same object. Participants explore potential causes for discrepancies in measurements, including calibration issues and environmental factors.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Homework-related

Main Points Raised

  • Some participants note that ideally, all thermometers should agree on the same temperature measurement.
  • One participant reports measuring 20°C with a thermocouple and 24°C with a thermomister, questioning the cause of the difference.
  • Calibration is suggested as a likely reason for discrepancies, with some participants agreeing that one or both devices may be poorly calibrated.
  • Participants mention that the object being measured may change temperature between measurements, which could affect results.
  • Concerns are raised about ensuring good thermal contact between the thermometer and the object, as well as the influence of ambient conditions on measurements.
  • There is a suggestion that the manufacturing process should include calibration, but doubts are expressed regarding cheaper devices.
  • Some participants express frustration about the lack of information available online regarding potential reasons for measurement discrepancies.
  • One participant humorously suggests that the discussion resembles a lab assignment, indicating a possible academic context for the inquiry.

Areas of Agreement / Disagreement

Participants generally agree that calibration issues are a significant factor in measurement discrepancies, but multiple competing views remain regarding other potential causes, such as environmental influences and measurement techniques. The discussion does not reach a consensus on all points raised.

Contextual Notes

Participants emphasize the need for more details about the measurement conditions and methods used, indicating that assumptions about the setup may vary. There are unresolved questions about the impact of environmental factors and the specific calibration processes of different thermometers.

barzani
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What is the difference in temperature with different thermometers for the same object?

Thanks !
 
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Hllo Barzani, :welcome:

Ideally they should all agree and measure the same temperature ... :rolleyes:

Is that really what you mean to ask ?
 
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Thanks

Suppose we have a one thing we want to find the temperature

Testing with thermocouple: 20 C

We will test with the thermomister : 24 C

With and ...

What is the cause of these differences?
 
I can't tell from here. One of the two -- or both -- may be wrong, badly calibrated, ... Or the object under scrutiny is warming up in the time between measurements, or ...

Thing to do is calibrate the two measurement devices: measure in water with ice to find 0 ##^\circ##C and in boiling water to find .. at least the same value (which may not be exactly 100 ##^\circ##C)
 
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barzani said:
What is the cause of these differences?

BvU said:
One of the two -- or both -- may be wrong, badly calibrated
I agree with BvU ... calibration would be the obvious reason for differences
 
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This is 2 reasons
The 1-body may change the temperature at intervals between them

2. No calibrating machine

Is there any other reason?

Why can not I find something on the Internet
 
davenn said:
I agree with BvU ... calibration would be the obvious reason for differences

good
?
but we have more another cause ?
 
We need more details on how you're doing these measurements. They may not be making the same measurement under identical conditions. Are these in contact with the surface of your object? How do you ensure that it achieves good thermal contact with the object and is not influenced by the ambient environment?
 
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barzani said:
This is 2 reasons
The 1-body may change the temperature at intervals between them
2. No calibrating machine
Is there any other reason?
Why can not I find something on the Internet
Things can go wrong for so many reasons that even the internet can't come up with all of them :smile:

By the way, this thread smells like a lab assignment and belonging in the homework forum...
 
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  • #10
barzani said:
The 1-body may change the temperature at intervals between them

yes, and that would have to be taken into account ... so therefore use both measurement systems at the same time to negate that problem

barzani said:
2. No calibrating machine
the thermometers SHOULD have been calibrated as part of the manufacturing process
For good quality ones, that shouldn't be an issue
For el cheapo ones, who knows what they use to calibrate the sensors. "You pay your money and you take your chances"Dave
 
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  • #11
BvU said:
Things can go wrong for so many reasons that even the internet can't come up with all of them :smile:

By the way, this thread smells like a lab assignment and belonging in the homework forum...
it is goodwe can also tell

The temperature-sensitive material is not directly in contact with air and is heated by thermal conductivity. This is a self-limiting factor؟؟؟؟؟؟؟؟/
 
  • #12
davenn said:
yes, and that would have to be taken into account ... so therefore use both measurement systems at the same time to negate that problem

the thermometers SHOULD have been calibrated as part of the manufacturing process
For good quality ones, that shouldn't be an issue
For el cheapo ones, who knows what they use to calibrate the sensors. "You pay your money and you take your chances"Dave
good thanks

see above my reply and tell me it is correct?
 
  • #13
RPinPA said:
We need more details on how you're doing these measurements. They may not be making the same measurement under identical conditions. Are these in contact with the surface of your object? How do you ensure that it achieves good thermal contact with the object and is not influenced by the ambient environment?
This is just an urgent question asked at the university asking and answering

Consider all the conditions for each device
 
  • #14
barzani said:
This is just an urgent question asked at the university asking and answering

Consider all the conditions for each device

So we have been doing your assignment for you?

Zz.
 
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  • #15
ZapperZ said:
So we have been doing your assignment for you?
The theme music from the movie "Jaws" starts playing softly in the background, and starts building...
 
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