What is Measurement: Definition and 1000 Discussions

Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. The scope and application of measurement are dependent on the context and discipline. In natural sciences and engineering, measurements do not apply to nominal properties of objects or events, which is consistent with the guidelines of the International vocabulary of metrology published by the International Bureau of Weights and Measures. However, in other fields such as statistics as well as the social and behavioural sciences, measurements can have multiple levels, which would include nominal, ordinal, interval and ratio scales.Measurement is a cornerstone of trade, science, technology and quantitative research in many disciplines. Historically, many measurement systems existed for the varied fields of human existence to facilitate comparisons in these fields. Often these were achieved by local agreements between trading partners or collaborators. Since the 18th century, developments progressed towards unifying, widely accepted standards that resulted in the modern International System of Units (SI). This system reduces all physical measurements to a mathematical combination of seven base units. The science of measurement is pursued in the field of metrology.

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  1. F

    Measuring AC current with an oscilloscope.

    I have a technical question, for research purposes. I have LED that we probe in AC mode. To measure the applied voltage in AC and the light-response in AC is no problem. However I would like to measure the current going through the device as well and I would like to link it to an oscilloscope...
  2. N

    SR830 lock-in amp measurement problem

    Hello I am currently have difficulties trying to measure dc-modulated voltages while applying a dc current, via Sr830 Lock-in Amplifier (LIA). Basically, I apply an 2 GHz ac current (amplitude modulated@10kHz and referenced to the LIA for lock-in measurement) and a dc current to my DUT...
  3. M

    Finding thermal expansion problems for measurement technique

    I am trying to find examples problems on thermal expasions related to the subject of measurement technique Google but I can't find them.. I don't know exactly what could be asked but the problem will be related to: "expansion of measurement device" is given, and "expansion of measured...
  4. I

    Repeating measurement of observables?

    I have a question on my homework set and I'm not sure the principle behind it: 1. Alice measured an observable F (a matrix) and passed the measured system immediately to another experimentalist, Bob, who is going to measure another observable G. Alice claims that she can deduce the experiment...
  5. T

    What is a dynamic spectrum measurement?

    I was going through Figure S9 in this paper yet don't quite understand how one can assign a probability density to a dynamic spectrum measurement as the authors do. To my knowledge, a dynamic spectrum simply displays the intensity for each frequency channel against time as shown in Figure 1C of...
  6. A. Neumaier

    A Key problems in classical and quantum measurement

    Quantum mechanical foundations are usually phrased in terms of measurement. I believe this is the main cause why these foundations remain shaky after almost 100 years of a good mathematical basis. Classical mechanics never had any reference to measurement in its foundations, and hence it was...
  7. A

    Linear Regression with Measurement Errors

    Hello, I have a set of data, two columns, and each datum has its measurement error like illustration shows below: x | y --------------|----------------- x1+/-xe1 | y1+/-ye1 . | . . | ...
  8. R

    How do I convert cubic picometer to cubic centimeter?

    Part of the question says: An unit cell has a cell edge of 288 pm. I got to the part where volume (288 pm)^3 = (288 x 10^-10 cm)^3 I have no idea how that equals 2.39 x 10^-23 cm^3 Only the Bold part ^
  9. G

    B Height measurement on other planets

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  10. yecko

    Instrumentation vs measurement

    What is the difference between the noun "instrumentation" & "measurement"? Thank you.
  11. P

    Meter R for V^2/R measurement?

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  12. N

    I Difference between measurement and passing through a gate

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  13. henry wang

    What's the error in 1 repeated measurement?

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  14. A. Neumaier

    I Many measurements are not covered by Born's rule

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  15. C

    Measurement standard for joules = Momentum in kilograms

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  16. A

    I The Arrow of Time and the Reversibility of Decay Processes in Physics

    Hello! I'm an Engineer by profession with less knowledge of physics, so please be basic with me. After recently being intrigued by the double slit experiment, I started to read more and more about the same. At most of the places, it says that as soon a sensor is kept near one of the slit to find...
  17. pittsburghjoe

    I Explanation for the Quantum Measurement Problem?

    Do we yet have an explanation for the Measurement Problem that Einstein would have been satisfied with?
  18. A

    Apprentice in fiberoptics and test and measurement equipment

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  19. J

    B Measuring c from Earth: Is the Speed of Light Affected?

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  20. quantumfunction

    B Do we measure the particle or the wavefunction?

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  21. T

    Electrodes liquid contact electromagnetic flow meter?

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  22. F

    I Definition and measurement of proper length

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  23. munirah

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  24. AdrianMachin

    Measurement Uncertainty Problem in MIT OCW 8.01x

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  25. J

    Hydrogen Atom: Wavefunction collapse after measurement of Lz

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  26. V

    I Measuring Coordinates in Strong Gravity: Schwarzschild Metric

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  27. C

    Finding uncertainty of a measurement

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  28. fsonnichsen

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  29. J

    B Why can't one metre be more than one metre?

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  30. Titan97

    B Position of a particle immediately after a measurement

    Say a particle was measured to be at a point C. Immediately after this, if i make another measurement, its given in griffith's book that the particle will still be found at C. Isn't this only possible if the particle was at rest?
  31. Q

    A Measurement of the Higgs Self Interaction

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  32. munirah

    How to calculate negativity measurement of quantum state?

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  33. Fizzics

    Power measurement of a servo motor using simple instruments

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  34. T

    Measure LDR Light with Microcontroller - 10bit Resolution

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  35. A

    Astronomers make first accurate measurement of oxygen in distant galaxy

  36. L

    B Bell's state measurement in the Bell basis

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  37. entropy1

    B Does weak measurement cause mixed state?

    Does a 'weak measurement' on the spin of an electron in a pure state put the electron in a mixed state of the previous state and the state of the measurement axis of the measurement?
  38. E

    I Question about superposition and measurement

    Hello everyone. I've gotten interested in quantum mechanics after binge watching a ton of documentaries about it. I've grown particularly interested in superpositions and the measurement problem. I'm not very good at math, so I can't understand the math behind it, but I like to take the...
  39. entropy1

    B Counterfactual definiteness and correlation

    If we assume there is no counterfactual definiteness, would that mean that measurements on entangled particles needn't be correlated, for if you don't compare the results, you just don't know if they do?
  40. entropy1

    I Macro state of a measurement device and correlation

    I have a question that seems to reflect my main concern with QM. Here it is: Consider a series of polarisation-entangled photon pairs that are sent in opposite direction to two measuring devices (e.g. at opposite ends of the universe). The measurement consists of detection of a photon after...
  41. entropy1

    I Is there a 'memory-effect' of measuring devices?

    If I'm correct, a series of with respect to some property entangled particles exhibits a correlation between several measurements of that property by means of two measuring devices. My question is: is it possible that between measurements the physical constitutions of the measuring devices...
  42. S

    B Has any experiment actually measured PI to many places?

    Ok, This probably seems a silly question, but has there been any 'serious' attempt to measure Pi PHYSICALLY, like in a lab, using say a light fiber in a circle and one down the radius? If so, where can I find the results/paper? Thanks!
  43. E

    A Progress in measurement of gravitational constant?

    I read that in 2014 the gravitational constant was measured by atomic intereferometry. Now I read that they speculate that measurements of G are in correlation with 5,9 years cycle. But, when we can expect new measurements of G? Are they in preparation?
  44. entropy1

    B Nature of collapse / does collapse exist?

    I learned that the moment a wavefunction collapse takes place is a matter of interpretation. So, I suppose the phenomenon 'wavefuntion collapse' is something that has to be witnessed by observation at some point to be able to establish it at all! So my question is: if collapse doesn't actually...
  45. S

    What equipment is needed for illuminated I-V measurements of a solar cell?

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  46. ShayanJ

    A Measurement problem in the Ensemble interpretation

    The ensemble interpretation asserts that QM is only applicable to an ensemble of similarly prepared systems and has nothing to say about an individual system and in this way, it seems, it can prevent the need for introducing the concept of wave-function collapse and so it may seem that there is...
  47. M

    I Conservation of energy in quantum measurement

    A measurement of an observable that does not commute with energy will generally cause a change in the expectation value of the energy. Is there a clear formalism to describe how energy is conserved overall?
  48. Kara386

    I What Causes a Measurement to Change the State of a System in Quantum Mechanics?

    I read that measurement changes things because we have to bounce photons off an object to 'see' it and that changes its position, momentum etc... But on the other hand, Griffiths' QM book seems to suggest we don't know what it is about measurement that changes the state of something. We don't...
  49. psycho_physicist

    Errors/ Uncertainty in measurement problem

    Homework Statement [/B] The surface tension (T) is measured by capillary rise formula T = \frac {rh ρg}{2 cos\Theta} . The quantities of ρ, g and θ are taken from the table of constants while the height and diameter are measured as h = (3.00 + 0.01)cm and D = (0.250 ± 0.001)cm Find the...
  50. V

    A Measurement without energy cost?

    Hi, On the context of Maxwell's Demon, it's accepted that Landauer's principle (the erasure of a bit of information requires kTln2 of work) gives a solution to the paradox. The erasure of a bit of information can be seen as the modulation of a double well potential, as in the right side of the...
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