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. Quarlep

    Is there a definitive measurement in the universe?

    In Every measurement there must be uncertanity.In length or In time everything.Lets assume we have a ruler and a rope.If I measure the rope I get a result but I can't say this is exactly true because there's a unncertanity in measurement.Lets suppoe the rope is 100 cm minus or plus 0.5 mm.The...
  2. S

    Designing a Strain Gauge Load Cell: Q&A on Force Measurement

    Hello, I'm trying to design a strain gauge load cell for force measurments. I have few questions regarding that. Q1: how to calculate the minimum froce that my load cell can detect? Q2: how to calculate the FSO(full scale output) of my load cell? Q3: Is there any way to measure the...
  3. M

    Quantum Measurement Problem: Nature of Matter or Nature of Probability?

    The objective of this post is to: (i) generate a discussion of whether results of the double-slit experiment address solely the nature of matter, or do the results also address the nature of probability; and (ii) to determine if there have been any comparably structured experiments outside of...
  4. Y

    How Does a Vernier Caliper Determine Precise Measurements?

    I have made measurements using Vernier Calipers. What I don't understand about them is the coinciding thing. How does one know the value of the last digit of the measurement by seeing which marker of the main scale coincides with the Vernier scale?
  5. MathematicalPhysicist

    Does the intrepretation affect the measurement?

    The question is as in the title. I feel that it doesn't change the mausrement.
  6. R

    Measuring Torque of a Stepper Motor Using a Suspended Weight Method

    1. The problem statement, all variables and given/known data I am trying to experimentally measure the torque of a stepper motor at various velocities. I'm not quite sure how this should be done. Here is a diagram of my proposed method so far: Basically a weight is to be suspended from the...
  7. P

    Measurement of irradiance of 2 beam interference

    Hi, I have an experiment set up to get two beam interference fringes. I would like to know how I could measure the actual amplitude of the irradiance from the experiment. I have with me a power meter and a CMOS camera. How can I go about this? Thank you
  8. cosmik debris

    Weak measurement with post selection

    I'm reading stuff about weak measurements with post selection and its likely ability to improve computational performance. What I'm curious about is whether weak measurement is a real thing or not. There are many papers showing how to do the measurements and the theory behind them, and then...
  9. naima

    Quantum Measurement: Sharp vs Unsharp - How to Determine?

    How can we see if a quantum measurement is sharp or unsharp ? can we measure unsharpness? Thanks
  10. ChrisVer

    Errors in Measurement [of time]

    I wanted to ask something concerning the errors... Why sometimes the errors are taken to be \sqrt{N} where N is your measured value (such as the number of counts from a detector) and why is it sometimes given as half of your device precision (eg a common ruler's error is 0.5mm)? In my case I...
  11. T

    Hooke's Law- measurement of mass/weight

    A body of unknown mass hangs from a spring and stretches it to 50 cm. If the spring constant is 104 N/cm determine: a. the weight of the body b. the mass of the body k = mg/∆L W= Mg mass : k = mg/∆L 50/104= .4807692308 weight : W= Mg .4807692308*9.8=4.711538462
  12. V

    Measurement Theory - Quantum Mechanics Q&A by VVS

    Hey, I have a question about Measurement Theory. I am reading Quantum Mechanics by Ballentine chapter 9 Measurement and Interpretation of States. Please check the following pdf for my question: thank you VVS
  13. M

    Pressure Difference measurement using Pressure Sensors / Transducers

    Dear All, I am not sure if this is the right place or not for this post so i apologise in advance if not. I am trying to find some pressure sensors / transducers to measure the pressure difference (with respect to static pressure) at points on a circular cylinder model installed inside a...
  14. G

    Current measurement of a PM DC generator

    Hi, I'm trying to use a small PM DC motor as a generator to convert mechanical energy to electrical energy. I couple that small generator to another DC motor with spur gears and I measure the current of that small generator while it is driven by the DC motor at fixed speed. The circuit of...
  15. C

    Teaching Error in Measurement Lab

    Hello all, as a recent graduate and a new teacher, I am living in Honduras and teaching the sciences in a high school setting. I did not study to be a teaching by got my bachelors in Spanish and Physics. I am working at a bilingual school and my resources are extremely limited. My question is...
  16. V

    How to prepare sample for cyclic voltammetry measurement

    I am doing research on synthesis of copper nano particles. I would like to have a cyclic voltammetry (CV) of this material but I don't know how to prepare sample. Please tell me the ways to carry out this measurement. Thank you so much!
  17. A

    Comparing the variance of two samples with differing measurement error

    Homework Statement This is a statistics as applied to astronomy problem. My stats knowledge is horrible. Anyway, the problem: For several hundred objects, I have a number of different properties for which I have a measurement & associated measurement error. For example, flux density and...
  18. F

    Current Measurement of Incident Proton ?

    The proton current in cyclotron are normally measured by Faraday Cup. However, I do not understand that if there is target material for the proton beam. Proton is fully stopped in the target material, for example, water. How the current is measured if it did not hit anything else?
  19. K

    Measurement Problem & Objectivity

    I have never been to the pyramids in Egypt. I'd love to go one day. I am sure their configuration will be just as others have seen, and as the visitor map describes. Why is it that my experience will correspond exactly with others' experience if I am collapsing quantum potential with respect to...
  20. H

    Individual Measurement Uncertainty vs. Standard Error of Regression

    Let's say a student does a simple experiment where she conducts 10 trials at each x value (at each value of the independent variable). She collects data over 30 x values, giving her 300 total trials. For each of the 30 x values, she averages the 10 y values and she calculates the standard...
  21. C

    Frequency measurement -- how to choose sampling ?

    Hi, let's say I want to measure the frequency f of a periodic signal. I may take N data points with an arbitrary timestep of T. The question is how shall I choose T for a fixed N to have the best accuracy? In principle the frequency resolution is 1/(N*T) when taking the Fourier transform...
  22. F

    Time dilation measurement and events

    Hello Forum, An event is a point in spacetime with spatial coordinates and a time coordinate: (x,y,z,t). An event does not have a duration since it only lasts for an instant t. We can talk about time duration to mean the temporal separation between two different events, correct? In the...
  23. MikeGomez

    Measurement Possibilities: The Role of Efficiency and Distance in Bell's Theorem

    Quote from this recently posted article. http://www.nature.com/news/physics-bell-s-theorem-still-reverberates-1.15435 “Quantum theory does not predict the outcomes of a single experiment, but rather the statistics of possible outcomes.” My question is not in regards to the statistics of...
  24. J

    Measurement of relativistic effects from a non-inertial frame

    I was just thinking about this, and from a perspective of an inertial frame, it's easy to see how distances contract, times dilate, simultaneity varies between observer and the speed of light is exactly c in each case. But what about non-inertial frames? In the presence of gravity almost...
  25. O

    Measurement Uncertainty: How do I calculate it?

    Homework Statement Hey guys! I'm new here, so firstly- hello! I've a exercise to from Metrology. Evaluate measurement uncertainty for the following measurement: 1. Measurement quantity: length of a bar L = 500 mm 2. Material of the measuring object: steel 3. Temperature range in the...
  26. PeterDonis

    Modeling a measurement as unitary

    This question is inspired by reading Arnold Neumaier's article on Everett's measurement theory: http://arnold-neumaier.at/physfaq/topics/everett Suppose I have a system whose state lies in a two-dimensional Hilbert space, and I want to model a measurement of its state as a unitary evolution...
  27. N

    Uncertainty principle & simultaneous measurement

    I have been reading and would be interested in feedback to the comments that I make, below. One of the points made in this paper is that the interpretation of the uncertainty relation needs to be re-examined in its relation to the viability of having simultaneous measurements of A & B. For...
  28. M

    T type thermocouple for Delta T measurement

    I am working on an experiment where I need to measure the Delta T across a heat ex-changer. I have two independent T Type thermo couple, one at the inlet and the other at the outlet. Both tied to an Agilent data logger. I normally put the data into an excel sheet and generate Delta T = T1 - T2...
  29. nomadreid

    Measurement of singularity as a particle inside event horizon

    Although the subject line might seem to put this question inside general relativity, the reason I put it in quantum physics is because I would like to know what happens when one treats a singularity as a particle. Obviously from outside the event horizon, one cannot do this, but inside the event...
  30. S

    Pure state, mixed state and measurement

    Hello guys, Homework Statement the problem goes as follows: "Which measurement should you do on a statistical ensemble of qubits in order to distinguish between the pure state |Ψ>= cos(θ)|0> + sin(θ)|1> and the mixed state ρ=cos^2(θ)|0><0| + sin^2(θ)|1><1| " Homework Equations I am not...
  31. W

    Low volumetric flow rate measurement

    Hi everyone, I'm currently a mechanical engineer interning at an HVAC company. I need to measure the resistance of a fluid through ductwork. The CFD shows a linear curve through a plenum when plotting R vs volumetric flow rate. For example, a straight rectangular box 1 1/16” by 2.5” and 3ft...
  32. M

    Why do we think that collapse occurs at measurement?

    Pardon me for my ignorance. This is a question of curiosity. I look for a concise logical argument as to why the community believes the following hypothetical situation and explanation is wrong. What justification is there for believing in waveform collapse at time of measurement? Is it...
  33. J

    Best way of measurement sodium wavelength?

    Hello everybody ,A friend of mine told me that best way (The most accurate) to do this is grating diffraction experiment , What u think? Thanks in advance
  34. T

    Volume Measurement (Dry Method)

    Hi: I have been working in this Project for a while now and I would like to share the results with you. Still needs some improvements; but it appears to be working fine so far. Please let me know your suggestions and ideas. Thanks.
  35. M

    Infinite square well, Probability of measurement of particle's energy

    Homework Statement Homework Equations The Attempt at a Solution I have managed to do the first 3 parts of the questions. The last two 4 markers are the ones I am having difficulties with. I have tried using the expansion postulate which states the wavefunction is equal to the...
  36. D

    Pump drive torque measurement problem

    Hi all! Basically I will soon be required to measure the torque required to drive a plunger pump which operates by an eccentric cam on the pump's driveshaft pushing a plunger up and down. So obviously the torque will vary through the driveshaft's revolution. The setup is as follows: Motor...
  37. N

    Thermofluids: Air Flow Measurement (Pitot & Venturi)

    Homework Statement I did an experiment to measure air flow using a pitot static tube and a venturi meter. First attempt: I connected both long and short manometers to the pitot static tube. Then I switch on the fan. The difference in manometer reading is 0.59kPa, which is the pressure. Then I...
  38. Y

    What is the best way to estimate uncertainties in a lab experiment?

    I am asked to indicate the uncertainty on the radius R of rotation of the plumb bob. Please see picture. Basically, there is a vertical shaft, over which is attached a horizontal shaft and a plumb bob is hung over with a thread on the horizontal shaft. The bob is attached with a spring to the...
  39. P

    Measure Pain: Is There an Equation?

    I was just wondering if there's a way to measure pain. I figured it'd be and equation like current. Like voltage would be the amount of pain, ohm would be a persons resistance to pain, and current would be the pain they actually felt.
  40. K

    Exploring Heat Capacity Measurements at Low Temperatures: A Comprehensive Guide

    Hi, I am looking for an introduction to heat capacity measurements at low temperature (10K). (For example for producing the linear dependence of the electronic heat capacity on T). I fail to find a simple introduction. Can anyone mention keypoints or a good source? Thank you!
  41. Y

    Measurement of voltage and current

    Is there a way in electrical engineering where I can convert 230 KV to 5 V such that the 5 V wave has same amplitude, phase and frequency as that of 230 KV.
  42. G

    What state do we have if we don't know if a measurement was performed?

    Hi, My question is partially motivated by this discussion. Suppose we have a pure state that is in a superposition for a certain basis, e.g. ##\left|\psi\right\rangle=\alpha\left| 0\right\rangle+\beta\left| 1\right\rangle##. Now a colleague of ours measures the state with respect to that...
  43. Jewish_Vulcan

    How do measurement units affect electrical devices?

    1.What do watts do and how do they affect an electrical device like a motor? 2. what do amps do and how do they affect an electrical device like a motor? 3. what do volts do and how do they affect an electrical device like a motor? I understand what these measurment are and how to solve for...
  44. S

    Aircraft: velocity + altitude measurement; simply or not?

    Hi! I'm breaking my head about the following problem: Consider an A/C at a certain velocity flying at a certain altitude. The A/C measures it's speed via the difference in total- and static-pressure and applying bernoulli. Now the aircraft accelerates. What happens? At this point I get...
  45. E

    Compression strength measurement

    Hello all, I have to measure the compression strength of a porous ceramic body (d=L=10 mm) using advanced force gauge, mecmesin and don't have any experience with it. The simple procedure, which I followed, was to measure the force at which the sample started to break, divided by the cross...
  46. Feeble Wonk

    Decoherence relationship to the measurement problem

    Decoherence relationship to the "measurement problem" I have heard the argument that "decoherence" in quantum states causes the quantum collapse to occur, and that this solves the "measurement problem". But I'm still left with a nagging question... Does decoherence only produce quantum collapse...
  47. K

    How Can dI/dV Help Determine Fermi Level and Band Gap in Semiconductors?

    I'm supposed to be working with an STM in the coming weeks to determining the Fermi Level of some semiconductor diamond films. I was bombarded with a lot of information by my lab supervisor and the bit of my notes about the calculation just says "Differential of voltage vs current allows us...
  48. stevendaryl

    Quantum Mechanics without Measurement

    I recommend the following paper by Robert B. Griffiths on developing the theory of quantum mechanics without giving a special role to measurements: http://arxiv.org/pdf/quant-ph/0612065v1.pdf In my opinion, it does not answer all the questions about locality and realism that come up in...
  49. Quarlep

    What is the meaning of a measurement expressed as 2.0 cm -/+ 0.05 cm?

    Hi I saw something in Wikipedia and I am confused. I saw something like this 2.0 cm -/+ 0.05 cm Whats that mean? My first opinion Between 1,5 and 2,5 My second opinion 1,5 cm or 2,5 cm
  50. T

    What is measurement unit of digital clear sound for devices

    like for example digital unit measurement for clear images in devices is ...pixel
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