Measuring Definition and 1000 Threads

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. S

    Measuring Etendue of LED sources

    How does one measure the etendue experimentally (when the area of the emitter and the angular distribution is not provided) in order to compare the focusing strength of two LED sources in an optical setup? Thanks!
  2. C

    What is the measurement of work in joules?

    Homework Statement If I push on a chair with 20 Newtons of force, but it doesn't move, I have done _____ of work. a. 20 joules b. 200 joules c. zero joules d. 100 joules Homework Equations W=Force x Displacement The Attempt at a Solution 0 joules =20x0
  3. T

    How do you measure static force without considering acceleration and velocity?

    Ignore the constant speed I have no clue how to do this problem
  4. Y

    Measuring current output from a floating current source

    Hi - I am by no means an EE, so please be aware I may have some fundamental flaws in my knowlege. I have a battery powered isoluation unit that takes some voltage in and provides either a voltage or current source output. I am giving it 1V as an input and according to the conversion ratio...
  5. B

    Measuring water pressure in long flexible tube.

    Hello dear sirs/madams, I would ask you to answer the following question. I have a flexible hose with a diameter of 5 cm, a length of 10 meters, it is in a vertical position and is filled to the top, with water. The hose is sealed on the top and the bottom. At the top of the hose...
  6. J

    Helmet Safety - Measuring Force of Impact

    My 12 year old daughter is conducting an experiment that includes testing various sporting helmets to determine which will protect your head best from a concussion. She is planning on dropping a 10 pound weight (approximate weight of human head) onto each side of the helmet. How can she...
  7. C

    Simultaneous measuring of two operators

    Hello everybody. I am new here, and also new to quantum mechanics. This is the question to which I can't answer neither in mathematical nor physical way. a,b → observables (like position and momentum) A,B → corresponding operators. "It is possible for particles to be in a state of...
  8. J

    Measuring thermal energy of surface contaminants

    Using a heat source to increase the temperature of an agricultural commodity like corn, could a thermal camera detect temperature differentials over time as the commodity cools, versus localized surface contaminants such as mold or fungus? I'm thinking yes in theory but the differences might be...
  9. J

    Measuring time delay before charged plates repel

    Imagine two parallel conducting plates set at a distance of several meters. If one charges the two plates simultaneously then one would expect a small delay before they started repelling each other due to the time it takes changes in the static field to propagate from one plate to the other...
  10. B

    Measuring temperature in a metal bar

    Good day ! I am trying to read a temperature on a heated cylindrical metal (steel) bar (about 15 mm in diameter) using a pyrometer. However I cannot measure the temperature on this bar. The bar has a rather dim shine on it and I think it affects the reading. Also, maybe because it has a small...
  11. M

    Factors to be considered measuring Magnetic Field of 130KHz

    I need to measure a magnetic field of Frequency of around 130KHz in all 3 X,Y,Z axis. I have a plan to make 3 coils perpendicular to each other and measure voltages from each coil in Oscilloscope channel. As per Faraday's law of induction. I could measure (dB/dt) as follows. V = - N A...
  12. D

    Measuring Voltage Across Two Points In A Series Circuit

    Homework Statement The series circuit is connected as follows: A 12V Battery -> 8ohm resistor -> 7V Battery -> 4ohm Resistor -> Earth. The problem states that if a voltmeter was connected from a point between the 12V battery & the 8ohm Resistor and connected to a point above the Earth then...
  13. Quarlep

    The uncertainty when measuring time

    Does any uncertainty when measuring time? Can we measure time definitely(hundred percent correct)
  14. P

    Measuring parallel velocity in rotating frame.

    Homework Statement At t=0 a police officer is located at (0,R) on a circular platform whose radius is R and which rotates around the z axis with constant angular velocity ω. The officer's velocity at that point in time is (ωR ,0). At that time, a bird leaves the center of the platform along the...
  15. B

    Measuring Power Consumption of a Light Bulb with a Dimmer Switch

    Hi guys, For a science experiment I've got to measure the power consumption of my circuit of a 100W incandescent light bulb connected to the mains AC, with a dimmer switch to vary its brightness. I was planning on just using one of those plug-in energy monitors with a digital display but...
  16. Jalo

    (Quantum mec.) Probability of measuring a given value of an observable

    Homework Statement Given the following hamiltonian and the observable \widehat{B} find the possible energy levels (a is a real constant). If the state is in it's fundamental state what's the probability of measuring b_{1}, b_{2} and b_{3}? Homework Equations The Attempt at a...
  17. J

    Measuring electricity passed to ground from an antenna

    First of all, excuse me if this question is too basic: I feel like it shouldn't be a struggle to understand, but the fact is it is. We put up an antenna to play with radio a little, and someone we were working with showed us that there's a reading on the voltmeter without any of the equipment...
  18. N

    Measuring the speed of light with chocolate and a microwave oven

    Got the following from a friend who teaches HS physics... Measuring the speed of light with chocolate and a microwave oven http://morningcoffeephysics.com/measuring-the-speed-of-light-with-chocolate-and-a-microwave-oven/
  19. L

    What is the collapse state after measuring Sx?

    Homework Statement So say I have a 1 qubit normalised state |ψ> = 1/√N(c1|z+> - c2|z->) and I make the measurement Sx and the measurement yields +hbar/2 as |x+> is a superposition of both z+ & z- basis eigenstates does the collapsed state end up the same as the original state? Or would I need...
  20. R

    Does the Speed of Light Change When Measured from the Sun?

    I know about the Michaelson-Morley expt. trying to measure the speed of light, once in the direction of motion of the Earth and then perpendicular to it. But the source of light was a torch (or similar) which is (obviously) on earth. I have somewhere read that it was also done with the source...
  21. H

    How can students derive a torque equation using scales and mobiles?

    Hi Folks: I'm pondering teaching torque and having students build mobiles as part of that. I started wondering if I could have them derive a torque equation. That started me wondering-if they were placing weights along different lengths of straws or skewers or something, could they weigh...
  22. D

    Probability of measuring E in a Hydrogen atom, and expectation values

    Homework Statement Hey guys, so here's the question: The energy eigenstates of the hydrogen atom \psi_{n,l,m} are orthonormal and labeled by three quantum numbers: the principle quantum number n and the orbital angular momentum eigenvalues l and m. Consider the state of a hydrogen atom at t=0...
  23. K

    Measuring size of a body cavity

    I have to measure the size of a cavity of a animal body(s). What is more important I need to measure it on several bodies and compare the results. The cavity is small and contains liquid. That liquid can be extracted and that sets the volume of cavity to 0. It's important to note that the...
  24. A

    Measuring Hair Thickness (Young slits)

    Homework Statement Hi, We're doing an experiment of measuring the thickness of a hair using a laser. So we took a hair, and a laser, and shot it through the hair, to receive the following pattern on the wall. The image of what we received (after red filter applied) on the wall is...
  25. F

    Measuring sum of two components of spin angular momentum

    Homework Statement What are the possible results of the measurement of the sum of the x and z components of the spin angular momentum of a spin-1/2 particle? Sx = Spin angular momentum operator x Sz = Spin angular momentum operator x Homework Equations The Attempt at a...
  26. R

    Measuring the Electron's Momentum Through a Slot

    Homework Statement Consider an electron incident on a screen with a narrow slot of width 2d. Assume that the electron is moving with velocity v in the direction perpendicular to the screen and that its wavefunction is uniformly spread over the slit and its vicinity, as shown. After going...
  27. B

    Searle's experiment for measuring the thermal conductivity of copper

    Hello, i'm doing my prep for my lab experiment tomorrow and have a few questions about the experiment. The schematic is attached. My lab script says the following; 2 questions. It says the precise rate of flow of water through the heat exchanger is unnecessary to know. Is this...
  28. J

    Measuring spin on electrons prepared in various directions

    Let's say we have 200 electrons. The first batch of 100 of those electrons are prepared in a way that 50% are UP in the x-axis while 50% are DOWN in the x direction. The order is unknown. The second batch of 100 electrons are prepared in the same manner but in the y axis. Bob picks one...
  29. S

    Measuring an angle in non-inertial frame reference

    In class, we came up with an equation, a=gtanθ, to calculate the acceleration of a car using a hanging pendulum in Earth's frame of reference (θ being the angle that the pendulum makes with the vertical when the car accelerates). So far, I know that that the pendulum moves in the opposite...
  30. J

    Entagled Electrons - measuring both x and y spin

    According to QM, given two entangled electrons A and B, if you measure the y-axis spin on A to be up, then you know electron B's y-axis spin is down. Also according to QM, if i understood it properly, you cannot then go on to measure the x-axis spin on B, because then you would know both y...
  31. E

    Measuring magnetic fields Will motors and metal frame interfere?

    Hello all, thanks for reading. I'm in the process of designing a machine that will move a hall effect sensor in 3 dimensions through a magnetic field and record readings. Before I started the design however, I wanted to see if there would be huge problems in how I envision this machine...
  32. M

    How Can I Measure Dosage of Ferromagnetic Powder in Kerosene?

    Hello, I am looking for a way to measure the dosage of a powder (made of metallic particles (ferromagnetic) that are 6 microns large) in a liquid solution that is kerozene. When mixed with the liquid a suspension is obtained that takes about one hour for the powder to settle down. Once...
  33. N

    Measuring Spin of Electrons Along X, Y & Z Axes

    σx|x>=+|x> σx|-x>=-|-x> These equations also follows for σy and σz corresponds states |y> and |z>. if we measure along axis X then X state vector let it go which means up spin and opposite not go through which means down spin. and also same for y and z axis. But, σx|u>=|d> σx|d>=|u>...
  34. D

    Measuring Speed in the Universe: A Puzzling Concept

    From what I understand, the speed of any object in the universe can only be measured relative to another object in the universe. . . . If this is the case then how can we say time slows down for an object traveling at super high speed. Who is to say which object is moving at super high speed...
  35. R

    Accuracy of a flow measuring instrument

    I have an instrument whose spec. sheet mentions Accuracy as 2% of FSD. The scale runs from 0 to 1000 Litres per hour. Does this mean if I check the instrument versus a gold standard calibrating instrument at a flow of 500 Litres per hour (which is our typical flow) the absolute error can be...
  36. ptownbro

    What are you really measuring as a battery discharges?

    Think for example a phone or any devices that shows the amount of battery power is left. It shows it as a graphic where you can deem whether it's full, 3/4 full, 1/2 full, 1/4 etc... or shows the actual percentage. What is that measure really showing you? Voltage? Amp hours left (which is the...
  37. B

    Does Length Contraction Occur If Measuring Tools Contract Equally?

    Consider an observer equipped with a good ruler and a rod. This observer measures the length of the rod and finds it 30 cm. Now this observer with his ruler and rod rides a spaceship and moves with a high speed. He then tries to measure the length of the rod using his ruler. According the SR...
  38. resurgance2001

    Measuring Plank's constant with LED's

    I have been trying to do an experiment measuring Plank's constant using LED's of different colors. The result I get is out by a factor of nearly two. I.e. I got about 3.7 x 10^-34 Js . I am not sure what I am doing wrong. Using a red Led for example, which has a maximum wavelength of...
  39. D

    Measuring speed of light with enhanced detectors

    Only but few may disagree that the inverse squared law affects speed. For example, not only lengths of far away vehicles shorten, (with increase in distances from obsevation) the moving vehicles generally seem to have "slowed" down; the direction either from right to left or vise versa. Please...
  40. F

    Measuring the momentum of a charged particle

    I am relatively new to particle physics, and I seem to have reached confusion already. I do not seem to comprehend how you could measure the momentum of a charged particle just by exerting force and a magnetic field on it. The formula F = Bqv is mentioned when I hear of this, which does not...
  41. T

    Measuring Membership, or Likelihood, of given Point

    Hello: I've three circles as seen in the image. Source: http://www.picpaste.com/Quantify-PwdfQxLB.png Within the innermost circle is a point. I'd like to determine the likelihood, or probability, that this point belongs to the innermost circle, the middle-circle, and outermost...
  42. B

    Measuring pressure using a manometer.

    Problem: 1. The pressure of a gas cell is measured with a mercurcy manometer. The mercury is 32.6 cm higher in the outside arm than in the arm connected to the gas cell. Calculate the gas pressure. Relevant equations/given data 2. p(Pressure at depth h) = p(Pressure of atmosphere) +...
  43. A

    Exploring the End of the Universe: Measuring the Unmeasurable

    where is end of universe and how can measure it?
  44. T

    Voltage Gating & Microscopic Observation for Measuring Optical Properties

    Hi, I'm wondering if there's any possible way to do voltage gating to a sample while observing it with a microscope, in order to measure its optical properties while changing its electrical parameters. Thanks
  45. A

    What is noted by +_5 in measuring cylinder?

    can anyone explain why is that noted?Most of them says that it denotes the error.why there should be an error in the instrument.Can't we make an instrument free of error?confused.
  46. H

    Measuring speed using phototransistors in Arduino

    Hey guys, I am working on a project where I am using two photo-transistors to detect the speed of a projectile. I am trying to measure the speed of a paintball but I am getting mixed results. When a slow moving object passes through the sensors the correct speed is displayed but extremely fast...
  47. V

    Measuring air transformer at resonant frequency

    Hi, I am in the process of trying to develop an air transformer but encountering unusual behaviour which I hope can be explained with some fundamental theory I don't yet know. My set up is as follows; - Two identical wound 13.3uH inductors designed to resonate at 4.364MHz. They are 10...
  48. R

    Measuring specs on a transistor

    Hey all, So I took apart an old computer monitor to try and harvest some of the hardware inside so I don't have to buy all that stuff for my hobbying, and I was wondering if it is possible to measure the specs on the transistors inside without having to put them into a circuit and see how...
  49. P

    Measuring velocity in empty space

    Let me preface this by saying I know very little about relativity. Last night a friend and I were discussing a particular scenario that will probably arise when humans begin to be capable of interstellar travel. Say you take off from Earth and accelerate to some velocity and then coast until you...
  50. R

    In need of a measuring a 100 ns force or pressure.

    As stated in the title, I am trying to send an ultrasonic pressure wave through a medium using a transducer. However, I am having trouble finding equipment or some type of method that measures within the 100 ns of the pressure applied. Digital Force Gauges and Impact Force Measurement systems...
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