What is Measuring: 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. willDavidson

    Measuring Temperature of PCB Via

    I am interested in measuring the temperature of a PCB via. Since vias are so small, I'm not sure how to go about this. Are there any methods for doing this? If I use a thermocouple, I would need to adhere it to the via wall somehow. Let's just say my via is 0.5 mm? The via would probably be...
  2. HarryLime

    Accelerometer vs. Gyroscope - measuring torque

    Summary:: accelerometer Vs gyroscope - measuring torque Torque can be measured with an accelerometer (tangential-acceleration): t = F*r and F=m*a, so we get a from the accelerometer, giving: t = m*a*r Nm Torque can be measured with an gyroscope (angular-acceleration): t = F*r The...
  3. I

    Chemistry Measuring Density of 7-Up: A Guide

    I know I need to measure the density of 7-Up. I can measure its volume, but I don't know how to find its mass. I also need to determine the composition of sugar in water, and compare 7-Up solution to the known sugar/water mixtures -- I don't know how to do these. Thanks.
  4. H

    Measuring the natural frequency of a spring-mass system driving force

    Hi, On a driving force graph ##y = displacement (m)## and ##x = time## where the external force start at t = 0 and the system is in equilibrium at x=0, it's easy to find the driving frequency. $$F = \frac{\omega}{2\pi}, \omega = \frac{2\pi}{T}$$ and we can get ##T## easily with the steady...
  5. B

    B Measuring a change in gravity - thought experiment question

    Imagine I hang a mass from the ceiling of a building using a rope. The mass is hanging 2m above the floor. Also tied "in line" with this rope, and between the weight and the ceiling, is a scale that measures the weight of the mass. Let's say the scale reads 10 Newtons. Now, between the...
  6. PhysicsTest

    Optimizing Phase Current Measurements with Shunt Resistors

    I have seen an application note of how to measure the phase currents using shunt resistors as shown below I am only confused with the connection when measuring the phase Ia current, it differs from the way the shunt resistor is connected for Ic and Ib, he could have done the same way like Ib...
  7. person123

    Optical Compact Device For Measuring Speed of Light

    Hi. This is an idea which I just happened to think of, and I was curious if it would be at all feasible. Here's a quick sketch I drew: The two curved mirrors should have a laser attached on one end and a video camera attached on the other. The laser would be tilted very slightly above...
  8. Astronuc

    Clair Patterson, Measuring Earth's Age, Discovery of Pb contamination

    I came across a story of Clair Patterson, who investigated the age of the Earth through isotopic analysis of lead in uranium, which evolved into a study of lead in the environment and the discoveries of widespread lead contamination and scientific misconduct on the part of various persons...
  9. LCSphysicist

    Special relativity — Observer measuring the velocity of a passing rocket

    I am a little confused with the text above. Actually, all is ok until 2.51, i think i am missing something. What is this? Another way to define gamma? (The doubt is not about the raising indices, neither about "n00 = -1", is just where does the equation came from. That is, the equation is easy...
  10. N

    B Earth's Hubble velocity and measuring Hubble at large distances

    Just curious. We can't figure out Earth's speed of travel through the universe due to the Hubble constant because that would be measured from the center of the universe and the center is located somewhere unknown to us except that it is beyond what we can perceive, i.e., more than about 63 Gly...
  11. RandyD123

    B Measuring the One Way Speed of Light

    Does this video even make sense? And if so, is it right or wrong?
  12. W

    Measuring Parameters for a Hybrid Rocket Injector Assembly

    I am interested in research on hybrid rocket technology and I would like to know if anyone has a known ideal way to measure the required parameters to find the below items. I am particularly interested in a cold flow test involving: Characteristics of the Oxidizer Flow Turbulent Intensity...
  13. J

    What is the Wavelength of Corona Discharge in High Voltage Testing?

    Hi, I am doing high voltage testing (20-35 kV or more) where I am trying to capture corona discharge. My DUT is in a dark test room with no light. I am using a Canon EOS T7 (2000D) DSLR to capture the corona. What I would like to know is the wavelength of the corona so I can do further...
  14. T

    B Measuring distance between two stars in a binary system

    Hello I am trying to teach myself some basic maths for astronomy from a book, namely trying to calculate the distance between two stars in a binary system. One thing i am confused with is what angular separation means and how it can be translated to true physical distance between them using...
  15. P

    I What is the correct way to calculate the area of the sky in square degrees?

    Most of the calculations that I have seen that measure the area of the Sky involve doing this: 2*pi*r = 360. => r = 57.295 degrees. And then 4*pi*(57.295)^2 = 41251.83 square degrees. Now the units check out fine, but here are the places where I am having trouble understanding this derivation...
  16. R

    I Measuring Entangled Particles in two different Basis

    Consider two entangled spin half particles given by the generic form of Bell Equation in Z-axis: ##\psi = (a\uparrow \uparrow + b\downarrow \downarrow)## where ##a^2+b^2=1## In a (2D) planer rotated (by an angle ##\theta##) direction the new equation can be given by: ##|\psi \rangle =...
  17. brainpushups

    Measuring Reflectance with a Digital Camera

    Background: This fall our initial plan will have high school students on campus 1 day per week and working remotely for the remainder of the week. I'm trying to plan for some at-home labs and projects. I came across http://albedodreams.info/how_to/how-to-calculate-albedo-yourself/ site which...
  18. LCSphysicist

    Measuring Blocks Equilibrium Displacements

    "The displacements of the blocks from equilibrium are both measured to the right. Block 1 has a mass of 15 grams and block 2 a mass of 10 grams. The spring constants of the springs are shown in dynes/cm." I don't know if i understood very well the notation, but i interpreted as F(t) acting only...
  19. S

    What is zero error of a measuring instrument ?

    Is this correct? "The systematic error in a measuring instrument due to non-uniform or wrongly marked graduation due to which a measurement may be less or greater than actual measurement is called zero error of the measuring instrument". Another one: The measuring instruments are combination...
  20. N

    I Question about The derivation of Lorentz equation in “The Behaviour of Measuring rods and clocks in motion”

  21. E

    Measuring corneal radius with illumination

    Since magnification is 0.0156, I have: m = -i/o 0.0156 = -24cm/o o = -1538.46 cm 1/f = 1/i + 1/o 1/f = 1/24 cm - 1/1538.36 cm f = 24.38 cm R = 48.76 cm However, when I look up the average corneal radius, the google results show ~5 mm. Did I do something wrong?
  22. S

    Measuring Agreement Between Experimental Values of Constant k

    Hello folks, Not strictly a homework question, but thought this might be the best place for it. If I determine (experimentally) two values for some constant k, is there a simple meaningful way to state their (percentage) agreement. For example, imagine I carry out two different experiments and...
  23. seb7

    I Measuring One-Way Anisotropy of Light Speed

    I've always thought that light could possibly be transmitted faster in one direction than the other depending on the velocity of its container - despite what the current understanding of physics says! The problem is that its very hard to prove, and to this end I've read through all the...
  24. H

    I Measuring the Speed of Light: How Did We Do It?

    I understand that the meter is defined from the speed of light (distance light travels in 1/299792458 of a second). But how did man measure this exact distance to this level of precision? With any apparatus, isn't there an unknown amount of bottleneck somewhere?
  25. K

    Measuring the Distance between the Fringes of a Diffraction Grating

    I have been preparing for a physics practical on diffraction. More specifically, we will use a CD as a transmission grating (by peeling off the reflective layer), and measure the distance between the fringes for a specific distance between the CD and the viewing wall. However, it is unclear...
  26. K

    Accelerometer with a Charge: Measuring Acceleration?

    Suppose we have an accelerometer carrying a charge. The charge density everywhere in the instrument is uniform, or at least what I mean to say is, the charge on any component is proportional to that component's mass. Now, in an inertial reference frame, we place the accelerometer in an electric...
  27. T

    I Measuring the force between air molecules

    If there was an atractive force between air molecules, how could this be measured? The force should be small. In the range of the force between watermolecules (hydrogen bond).
  28. A

    Carbon atom larger than a water molecule? Measuring a molecule's size?

    So there's a website here: https://learn.genetics.utah.edu/content/cells/scale/ That shows the scale of various entities (coffee bean, viruses, a carbon atom, a water molecule etc). It says that the carbon atom is larger than the water molecule. This is based on the 'van der waal radius'...
  29. Cheesycheese213

    Measuring the coefficient of friction

    Hi! Sorry if this isn't a good question, but for an experiment, I wanted to try measuring the coefficient of friction of frozen solutions, but wasn't sure how to do it? I thought that since ice would have a low coefficient of friction, it would be interesting to see if solutions with water and...
  30. Cheesycheese213

    Best type of map (projection) for measuring distances?

    Hi! Sorry if this isn't the best question, but I've been trying to do a project where I thought it would be interesting to talk about coastlines. I downloaded a GIS (QGIS) to try and see if I could roughly measure all the continents for myself, but I haven't really done this before, so I wasn't...
  31. F

    Measuring the Transverse Velocity of a Galaxy

    See the attached figure. I understand that we look for the apparent transverse velocity v , for example through v = d/t (d - distance, t - time). The distance to the galactic nucleus is known as D. Though I am not sure how to read off the time from this figure.
  32. G

    A Measuring Deflection of Star Light During Eclipse: Separating Space-Time Effects

    There is the famous experiment of measuring the "movement" of a star close to the sun during an eclipse. The stars position is determined before the disc of the sun moves just under it and than the position is again measured when the sun moves just "under" the star. The star will have appeared...
  33. Boltzman Oscillation

    Engineering Measuring the damping frequency from an oscilloscope reading

    I know the following equations for if the damping ratio is less than 1: $$\sigma = -\zeta \omega_n$$ $$\omega = \sqrt{(1 - \zeta ^2)\omega^2_n}$$ I am given the following circuit that I built on LTSpice: Measuring the voltage between node 2 and ground (blue), and the voltage Vc4(t) (green) I...
  34. Like Tony Stark

    Measuring position and velocity from a non inertial reference frame

    I) For ##A##, the positition is ##\vec r=(0;V_0 . t;0)##. For ##B##, we have ##\vec r_A=\vec r_B + \vec r_{A/B}##, but ##\vec r_{A/B}## is equal to zero because they have the same origin, so the position measured from ##A## is equal to the position measured from ##B## II) For ##A##, velocity...
  35. alfab

    Measuring Water Temperature & Diffusion Coefficient with Pollen

    Problem: We wish to find the temperature and the diffusion coefficient of water by measuring the velocity of pollen grains in the medium, due to brownian motion and other forces. Attempt: We have a video clip and are using the program Tracker to measure the position of the pollen grains over...
  36. Like Tony Stark

    Measuring position, velocity and acceleration in relative motion

    Well, ##r(t)## in ##A## is just a vector ##(0;y)## because is tangent to the trajectory. Then, from the perspective of ##B## the particle moves in an uniform circular motion. Is this right? The velocity from ##B## must be ##\omega##, right? And what about acceleration?
  37. P

    Measuring Magnetic Field Strength of a Cylindrical Magnet

    Hello, Today I am wondering if anyone can help me quantify the strength of the magnetic field created by a permanent cylindrical magnet. I have been able to find equations online for the strength of the field within the z axis, (ie. the longitudinal length) but I would like to know the strength...
  38. electr0dave

    How can I mix gases in a chamber measuring only pressure and temperature

    Hello all! Basically I intend to create an environment inside a chamber with variations of CO2 percentages, using electrovalves. The mixing gas is always compressed air + CO2. For example: create a 50% CO2 concentration with a total pressure of 2 Bar. The chamber is closed, and compressed air...
  39. neilparker62

    I Measuring the Helium Spectrum: Friederich Paschen 1916

    Re page 14 of following reference: https://zenodo.org/record/1447321#.XSyx3z9LjIU If I understand correctly this page is showing a set of measurements for the fine structure of singly ionized Helium at +- 4686 Angstrom. Can we figure out from this which specific transitions are being measured...
  40. weezy

    Measuring Tensile Strength in an alternative way

    So I've been looking at a few material tests and they all start with a rectangular sample of the material, loaded into a machine which extends them by increasing load at a constant rate and measures the strain/stress till the point of material fracture. The yield stress is measured in usually...
  41. M

    B Measuring Fictitious Forces in a Closed Box

    I was reading the following article: https://en.wikipedia.org/wiki/Fictitious_force When I came across this passage: "This led Albert Einstein to wonder whether gravity was a fictitious force as well. He noted that a freefalling observer in a closed box would not be able to detect the force of...
  42. Roy S Ramirez

    Measuring the Discharge Coefficients of a Rocket Injector

    Hello everybody! I hope you are all doing well. I built a liquid rocket injector and the following feed system: I started to do hydro-static tests (cold flows) and a program I wrote records all the data for me (except for the flow rates which I measured experimentally by collecting the water...
  43. H

    I Measuring Mass of a Bowling Ball Dropped into a Black Hole

    In a recent thread we discussed the idea that an object slowly dropped into a black hole, can have its rest mass recovered, as energy, if slowly brought to a halt at the event horizon. Once the object is dropped, it would be unrecoverable, and the BH would gain no new mass. I am under the...
  44. Isolde Wilde

    B Can color be used for measuring density?

    I am wondering if can the colour of a liquid be related to its density?
  45. B

    B Measuring a circle and the Uncertainty principle

    I have been trying to see if my understanding of uncertainty principle is right. So I thought consider a circle. for this augment we will look at its diameter and it circumference. Suppose you get a length of string and make a exact measure of the circles circumference using this length of...
  46. Foppe Hoekstra

    I Length Contraction: Measuring a Difference of 55 Nanometers

    If the table (with the mirrors, beamsplitter, etc.) is rotated 90 degrees, one arm will get shorter (due to lengthcontraction) because its longitudinal speed goes from zero to 30 km/s (our speed around the sun) and the other arm will get longer as its speed goes from 30 km/s to zero. So with a...
  47. fluidistic

    How to mathematically write down a probability of measuring a particle

    Consider a system of 2 identical electrons that are confined in a region so that there is a single wavefunction describing the whole system. In several textbooks one can read that the probability to measure the position of an electron in region near ##r_1## and the other in a region near ##r_2##...
  48. J

    B Proietti 2019 experiment: Doubt in measuring A1(B1)

    Hi everyone! Sorry for the bad english! Paper: https://arxiv.org/abs/1902.05080 I guess I understood the experiment until the moment Alice and Bob chooses to measure A0(B0) or A1(B1). I guess it's kind of straightforward that without a bell state measurement with photon alfa(beta) and photon...
  49. S

    A Measuring Quantum Vacuum Fluctuations

    I have been reviewing potential methods for measuring Quantum Vacuum Fluctuations that I might be able to implement in a home hobbyist environment. Must be room temperature devices. I have seen that there are only a couple of possibilities: The Tunnel FET and the Single Electron Transistor. I...
  50. F

    I Measuring energy and its change

    Hello Forum, I understand that energy, either kinetic is a relative quantity whose value depends on the frame of reference and its motion. Is that true for potential energy as well? I read on a physics book that only changes in energy can be measure. What does that exactly mean? Why can we...
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