What is Model: Definition and 1000 Discussions

A model is an informative representation of an object, person or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin modulus, a measure.
Representational models can be broadly divided into the concrete (e.g. physical form) and the abstract (e.g. behavioural patterns, especially as expressed in mathematical form). Of particular importance in the modern context, conceptual models are central to philosophy of science, as almost every scientific theory effectively embeds some kind of model of the physical or human sphere.
In commerce, a model might instead reference a specific version or configuration of a product offering, rather than functioning as a representation of something else.
In taxonomic settings (e.g. biology, architecture, art) a model is sometimes a particular instance of a set of related entities (species, built structures, artistic compositions) chosen as a convenient reference point around which to build discourse; such a model is almost always chosen to typify some central tendency of the group, exemplify the group's defining characteristic, or reify the group's historical lineage.
Kinds of models include:

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  1. Geth

    Model electrodes and plates in ANSYS

    Hello, I am trying to model an electric setup in ANSYS Workbench. I want to model some charged surfaces surrounded by charges. Then these are in an electric field created by two electrodes. I uploaded an image for visual aid. I have been playing around with the software for a while an am...
  2. Anchovy

    A SU(5), 'Standard Model decomposition', direct sum etc.

    This has turned out to be a long question to type out so I apologise, but I don't think it's too hard to follow or read through quickly and I believe the actual question itself may not be too complicated once I get round to asking it. You can possibly skip to the last few paragraphs and still be...
  3. amjad-sh

    Tight binding model (covalent bonding)

    Homework Statement (linear combination of atomic orbitals): Lets consider two atoms which are bond together with a covalent bond. Let's consider any sets of wavefunctions |n\rangle for n=1,2,...,N. Let's call orbital |1\rangle around nucleus 1 and orbital |2\rangle around nucleus 2 and so on...
  4. J

    Tracking Micronutrients in Anaerobic Bioreactor System

    How can we make a mathematical model for tracking micronutrients in an anaerobic system (Bioreactor) that has different chambers. The feeding ( Sargassum spp.) inters in the first chamber and should pass through the system 'til the last chamber. We know the concentration of micronutrients( Fe...
  5. Deepak K Kapur

    The use of the word 'model' in science

    It is often said that science is a 'model' of reality out there. I think this statement is wrong. It presupposes that there is a reality that is beyond 'modelling'. Suppose, someone really finds out the reality 'as it really is'. ( I am not saying there surely is). She would first of all...
  6. M

    EQualityCoin- What type of model is this?

    Hi everyone, I've been working on developing a crypto-currency called eQualityCoin for a while now and hoped someone here might be able to help me "classify" the system in a formal mathematical sense. The system's main feature is a simple rule for how it determines a purchaser's exchange...
  7. Z

    A A discord in analysis of a closed vs. open system model

    Is there anywhere in physics textbooks , or anywhere else, a section on KINETICS OF ROTATING FLEXIBLE, CONSTRAINED BODY BY GRAVITY ( TURBINE ROTOR IN BEARINGS), NON-INVARIANT (Time -translation invariance by Noether’s theorem), WITH ECCENTRIC MASSES, TORQUE DRIVEN AT NON-CENTROIDAL AXIS...
  8. srinaath

    Dynamic model of non-linear system

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  9. F

    How Do You Diagonalize the Chiral Symmetry Breaking Term for Pion Masses?

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  10. J

    I Electron motion in the plum pudding model

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  11. S

    A Help understanding ARIMA Model and ACF

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  12. J

    An application of free fall (DE) model to industry

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  13. S

    Regression Model Homework: E(Y)=Xθ, Cov(Y)=σ2W - 65 Chars

    Homework Statement Suppose that we observe ##i=1,2,\ldots,n## independent observations that can be modeled as follows: $$Y_i = i(\theta+\epsilon_i) \quad \text{where} \; \; \epsilon_i \sim N(0,\sigma^2).$$ 1. Write the above as a regression model, ##E(Y) = X\theta##, ##\text{Cov}(Y) =...
  14. E

    B Time Dilation Model & Wave Interference: Newbie Questions Answered

    I have some newbie kind of confusion The model in question is taken from wikipedia: and If, in the first model, the light ray is reflected back to its source, could there be some kind of detectable interference at the midpoint (where the blue arrows are)? If the answer is yes, would this...
  15. A

    What is a positive sequence model of an induction machine?

    I'm trying to understand a 3 phase induction machine model used as a generator in a Doubly Fed Induction Generator (DFIG) arrangement in Simulink. In this model for the induction generator component, they have stated that the model is a "Positive sequence model" of the induction generator...
  16. F

    Perturbation matrix: free electron model on a square lattice

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  17. Z

    Automotive Vehicle and Engine Simulink Model Engine rpm calculation

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  18. Andy24

    Model Rocket- What does the 'v' in drag=kv^2 really mean?

    Hello! I am predicting the peak altitude of a model rocket based on some ground tests. I know that Total Force on the rocket=Thrust-mg-kv^2 but am stuck as to which value for 'v' to use? Is it the velocity of the rocket with the effects of gravity and air resistance taken into account or the...
  19. W

    Ratio of size of prototype and model

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  20. J

    A What is the best Quantum Model to solve many body problems?

    I know to describe Quantum Mechanical systems we can use: -Schrodinger equation -Feynman Path Integral method -Heisenberg Matrix formulation Well my question is, if you want to calculate molecular properties, and want to understand biochemistry (protein), you have a system with several...
  21. Andy24

    Coefficient of Drag on a model rocket

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  22. C

    I Georgi-Glashow model of W bosons/photons

    The following is from my notes: In 1972, a model was proposed by Georgi and Glashow as a candidate theory describing W bosons and photons with Lagrangian $$\mathcal L = -\frac{1}{2} \text{Tr} F^{\mu \nu}F_{\mu \nu} + (D_{\mu} \phi)^T (D^{\mu} \phi) - \mu^2 \phi^T \phi - \lambda(\phi^T...
  23. V

    Adjusting the Model: d = 12 sin (30(t-5)) + 14

    Homework Statement Modify the model d = 12 sin (30(t-5)) + 14 to match the new data which is as follows; maximum water depth is 22 m minimum is 6 m, and the first high tide occurs at 5:00am. Homework EquationsThe Attempt at a Solution The answer is y= 8 sin (30(t-2)) + 14 Ik it's 8 b/c...
  24. Bran

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  25. J

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  26. I

    Nuclear shell model, spin and parity predictions

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  27. fluidistic

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  28. G

    B Quantum Model of Contact Forces

    I'm curious about contact forces, such as the normal reaction force on a book resting on a table. I've read that it's actually the electromagnetic force, but atoms are electrically neutral and there is no ostensible repulsive force between electrons and the nucleus, so I have some doubts. Has...
  29. S

    How Does Intermolecular Potential Energy Behave in Ideal and Real Gases?

    Homework Statement In the kinetic model of an ideal gas, it is assumed that: A. The forces between the gas and the container are zero B. The intermolecular potential energy of the molecules of the gas is constant. C. The kinetic energy of a given gas molecule is constant D. The momentum of a...
  30. Matt atkinson

    State Space Model for a Circuit R, L, C

    I have been struggling to solve the following problem for days. I was given the state space model of a circuit and asked to determine the system elements. So basically, I think I have to find a suitable circuit which describes the state space equation. I am not really sure how to approach this...
  31. debajyoti datta

    I Rutherford's Atomic Model: Rejected by Physicists?

    << Moderator's note: thread spun off from https://www.physicsforums.com/threads/radiation-from-a-square-loop-of-current.868648/ >> But Sir, then why was Rutherford's atomic model rejected by physicists?
  32. astrof

    A Numerical simulation the n-body problem under SR model

    The problem is a simple n-body problem: there is n charged particles - electrons, protons, or other particles; we have the initial parameters: a mass, charge, position, velocity, at a time t = 0. In a standard (classical) numerical computation of the n-body problem I can use any numerical...
  33. Spinnor

    I Zig-zag model illuminates helicity vs. chirality?

    Can we use the Zig-Zag model of the electron to get an intuitive understanding of the difference between helicity and chirality? Suppose we have a long and narrow cylinder where the spin 1/2 massless zig and zag particles bounce between the top and bottom of the inside of the cylinder at the...
  34. S

    A Treatment of singlets in the Hubbard model

    I'm using the general Hubbard model (H = U \sum n_{i,\uparrow} n_{i,\downarrow} - t \sum (c^{\dagger}_{i,\sigma} c_{i+1,\sigma} + c^{\dagger}_{i+1,\sigma} c_{i,\sigma})) to solve for eigenstates of simple quantum dot configurations. For the case of a double dot with two electrons in singlet...
  35. vinicius0197

    Project and Construction of Arduino controlled model rocket

    Hey folks. I've done a little bit of research into model rocketry and I'm stuck with the idea of designing and projecting a rocket to put into practice all the engineering I'm learning in college - I'm into MechE. I want to start simple, doing a few tests and learning the basics - types of...
  36. D

    "Isolated system model" can someone explain this to me?

    Homework Statement Two objects are connected by a light string passing over a light, frictionless pulley as shown in the figure below. The object of mass m1 = 4.80 kg is released from rest at a height h = 4.40 m above the table. (a) Using the isolated system model, determine the speed of the...
  37. A

    Creating a Floating Oil Rig Model with Recycled Materials | Size: 60x50x50cm

    I have to make an oil rig model with the size of 60x50x50cm by using recycled materials and weight will be added from 1 kg to 10 kg depends on its stability. How can I make this model float? thank you
  38. S

    Heisenburg Ferromagnetic Model

    Homework Statement There are several parts to this question, however I could complete these parts. It is just an equation used in the prior part to the question that is need to solve this: If we define \begin{equation} \sigma_{n}^{-}=\sigma_{n}^{x}+i\sigma_{n}^{y} \end{equation} and with the...
  39. Z

    How to define paramaters of perzyna viscoplastic model?

    Hello everyone i want to model viscoplasticity using Ansys APDL, Perzyna and Peirce or Anand model offer us to do this modeling, and each modèle Contains different parameters. the question is: how to determine the parameters (if we can determine them experimentally, what is the concerned test...
  40. C

    I SU(3) quark model and singlet states

    'In the SU(3) quark model there are two singlet vector states $$|\omega_8 \rangle = \frac{1}{\sqrt{6}} \left(|u \bar u \rangle + |d \bar d \rangle - 2 |s \bar s \rangle \right) $$ belonging to the octet and the pure singlet state $$|\omega_1 \rangle = \frac{1}{\sqrt{3}} \left(|u \bar u \rangle +...
  41. Iqbal94

    Question about a dynamic equation of a crane model

    Hi guys, I have a question on the fundamental dynamic equation as I am not sure if my equation is correct. I am doing an analysis on a portal crane to find its application factor, somehow I couldn't get the desired value for the velocity of each masses as I couldn't find the tension of the...
  42. R

    I Differential number of particles in Fermi gas model

    I'm practicing for the Physics GRE, and came across a question that has me stumped. "In elementary nuclear physics, we learn about the Fermi gas model of the nucleus. The Fermi energy for normal nuclear density (ρ0) is 38.4 MeV. Suppose that the nucleus is compressed, for example in a heavy ion...
  43. D

    Thermodynamics- UNIQUAC activity coefficient model

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  44. DianaHerberg

    B Find 3D Models of Waves | Get Creative with 4D Displays

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  45. Toxis

    I VR/AR big bang model (Virtual Reality Simulation)

    Hi, I have a silly question, Could one, in theory make a accurate model of the life of our universe that one could look at from within. Let's say I put on my VR/AR goggles, 'there' Iam elevated from the earth, then I remain static, and the time begins to rewind. At some point I maybe hear...
  46. P

    I Shell Model: Filling Up Nuclei

    I'm a bit confused about how things fill up in the shell model. Here is my understanding: the potential we are working with is the net potential due to the other nucleons that a proton or neutron feels throughout the nucleus; it is a combination of a square and harmonic oscillator potential...
  47. P

    I Basic band theory question, free electron model

    Hello, I am trying to figure out the width of bands in a 1-dimensional lattice. Here is a short derivation from the book I am reading: if we approximate the free electrons as being in a square well then the energy levels are ## \frac{\pi^2 \hbar^2 n^2}{2mL^2}##. If there are ##N## ions...
  48. Berenices

    I Does The LCDM Model need reworking?

    Greetings, I am slightly curious as to whether the LCDM model may require a slight tweaking. The reason I am curious is because I recall reading a while back that removing the homogeneity assumption from our current models could assist in accounting for some of the large-scale structures, and...
  49. vetgirl1990

    Phase difference between waves in two-slit model

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  50. vetgirl1990

    Finding the angle of phase difference - two slit model

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