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:

View More On Wikipedia.org
Recent contents Top users
  1. N

    Bohr's atomic model and Bohr and Rydberg equations

    Hello, well, I am totally new to this section of physics so my question may sound ridiculous, but here it is: When I was reading about the Bohr's atomic model, I learned about the Bohr and Rydberg equations (E=-2,18*10^18*Z^2/n^2 J and 1/λ=RZ^2(1/n1^2-1/n2^2) as well as their proofs. Then I...
  2. B

    Problem with shell model and magnetic moment of Lithium-6

    I have a problem with the calculus of magnetic moment of Li-6. The configuration of protons is 1p_{3/2}, and the neutrons' one is the same. I have to add the magnetic moment of uncoupled proton and uncoupled neutron. I use the following formula for J=l+\frac{1}{2} (J is the particle...
  3. W

    Effects of size and speed on model airplane crashes

    I am looking for an equation that correlates material failure and collision speed; so that I can better understand the effects of size and speed on model airplane crashes. Is there an equation that correlates an object's length and speed to material failure, for one-dimensional elastic...
  4. U

    Looking for help with a Ring World Model

    Hello everyone. I am world-building for a fantasy setting. I've had an idea and I'm not sure if it's feasible or not. I'm trying to model a non-standard world type and I wanted to see if I'm on the right track. The idea is for a ring world. The outside is habitable. I've already got a...
  5. ChrisVer

    How can I calculate the F-terms for chiral superfields in a no-scale model?

    In case you have the Kahler and super- potential K,W: K(T,S,C) = -log (S +S^{*}) -3 log ( T+ T^{*} - C C^{*}) W(T,S,C)= C^{3} + d e^{-aS} +b with T,S,C chiral super fields, b,d complex numbers and a>0. I tried to calculate the local F-terms arising from this. The local F-terms for the i-th...
  6. G

    How to model demand for pricing?

    Hi! I'd like to understand how to model consumer demand given a price I set for a good. Therefore for a specific good I'm given the current prices of competitors and maybe some historical values for number of goods sold by competitors and me at a specific price at previous times. I would...
  7. marcus

    Radical new cosmic model (Barrau Linsefors one-up Penrose)

    ==from conclusions section on page 4 of Barrau Linsefors June paper== V. REBIRTH OF THE UNIVERSE AND TESTS OF THE MODEL In the far future, huge patches of our universe, with radii larger than the Hubble scale, will be completely empty. They will be pure dS spaces. If the model suggested in this...
  8. tlnarasimham

    In the standard model gravitron is a particle but Higgs boson is not?

    In the standard model gravitron is a particle but Higgs boson is not. The Higgs field causes particles to acquire mass. Mass generates a gravitation field. Is gravitron is in any way related to Higgs boson? Is the Higgs field any way related to gravitation field?
  9. GalileoGalilei

    The Ehrenfest wind-tree model

    Homework Statement A collection of fixed scatterers ('trees') are placed on a plane at random. The trees are oriented squares with diagonals along the x- and y-directions (cf attached picture). The number of trees per unit volume is n, each side is of length a, and na^2 << 1. There are...
  10. L

    Model for free market growth

    Hi guys, I am not economist, but can anybody tell me whether there is a mathematical model for growth in free market economy without state intervention? Where can I look them up? Thanks.
  11. RJLiberator

    Bohr Model Problem (Part 2 - Updated)

    Greetings again, So I realize my last thread: https://www.physicsforums.com/showthread.php?t=757685 became chaotic with my thoughts and un-clear writing. I've re-did the work to make it easier for people to understand my thought process. The two questions are as follows: 7)Calculate the...
  12. RJLiberator

    Help with the Bohr Model Problem

    Okay, I am in need of some guidance: 7)Calculate the wavelength that corresponds to an emission of energy of 1.977x10^-19 J. Okay, well here is my thought process initially: Change in Energy = hc/wavelength. First question: Is 1.977*10^-19 THE change in energy? OR is that the Energy...
  13. W

    Why do we still teach Bohrs Model?

    Why do some education systems still continue to teach Bohr's model even though it's seen to be incorrect?
  14. A

    Mathematical Model Homework: Lengthen Time until Shock Stabilised

    Homework Statement [/b] Develop a mathematical model that would lengthen the time until the shock stabilised by the given time. T= 2.51 show mathematical analysis of the situation d(t) = -5e^(-5t) cos (10t) is the original equation for a deflection of a rod in centimetres where t is time...
  15. I

    I want to build a mini-hoverboard (2" by 8" scale model)

    For the past week or so, me and a buddie have been trying to figure out how to make a mini-hoverboard kind of this, now it doesn't even have to look like a hoverboard we just want it to be able to get off the ground with 2 fans. What we were going to order was all this stuff...
  16. L

    How do D-Brane arrangements affect particle masses and the standard model?

    Hi. I've been reading that if one places a Dp brane in a 10d space then it's possible to have a string with [11] Chan-Paton index i.e. a string that starts and ends on the same Dp brane. Since the separation of the brane with itself is 0, this string corresponds to a massless particle. Why is...
  17. C

    Is there any good review articles on quark fragmentation model?

    I am planning to do some work on quark fragment into hadrons, and I have heard some models like Lund Model, feynman-field model and so on. Is there any good review articles on the topic of fragmentation model? (Recent years is better) Best Regards!
  18. O

    Distribution to model time between web page accesses

    I have a formula to get an average time that an average user spends reading a web page before going to the next one, that takes as input the number of words on the page. I want to use this in conjunction with a probability distribution to try to accurately model an 'average user' that is not...
  19. A

    Error propagation when dividing by fitted model

    Homework Statement I am taking a dataset of intensity vs. frequency (which I'll call dataset I_1), and fitting it with a linear model (I_mod). I want to divide another intensity vs. wavelength data (I_2) by this fitted model to get fractional changes in the second data set compared to the...
  20. G

    2D heat conduction of layered composite model

    Hi, I am trying to formulate a 2D model to calculate the temperature change over time in a composite material. The material consists of several layers, and is heated from all edges by a known temperature vs time profile. I was thinking of creating a finite element model. Can someone...
  21. A

    The effect of aerofoil shape on rubber powered model aircraft

    Model aircraft display a wide range of aerofoil shapes, and many of these models fly despite the shape of the cross section of the wing. Models with flat wings, cambered wings, thick wings, thin wings - all of these fly succesfully. What is the function of aerofoil shape on free flight...
  22. M

    A model of galactic star formation

    Hello, I am looking for a model of galactic star formation that I can study. Particularly, I would like one that works well for mature galaxies like the Milky Way. It also should be relatively recent as well. I am primarily interested in the yearly rate of star formation for galaxies like the...
  23. C

    Atomic Model of Hadrons mass of excited particles

    So in a lecture I'm reading up on we are given questions to answer during the lectures with no answers, and for this particular lecture the answer has been omitted and it is in none of our textbooks. But basically it says that a proton and a sigma plus, both have the same quark composition...
  24. S

    Light bending in the hot plate model of curvature

    Light bending in the "hot plate" model of curvature In the Feynman lectures, feynman describes the hot plate model of space curvature and shows that light is bent around the center of the plate, see Fig. 42-6 http://www.feynmanlectures.caltech.edu/II_42.html#Ch42-S1 However, the hot plate...
  25. tom.stoer

    Standard model gauge anomaly cancellation

    There are quite subtle gauge anomaly cancellations in the standard model. Does anybody know a good summary about the algebraic constraints for number of fermions per generation, value of electroweak charges, etc.?
  26. V

    Someone willing to help me understand this economic model?

    I have problems understanding the economic model. I need to write an introduction, but unfortunately cannot understand the main point. Will be grateful for any help! Thank you in advance!
  27. C

    Bernoulli's with Resistances - model flow between oil filters

    Bernoulli's with Resistances -- model flow between oil filters Hey guys, It's been a while since I was in school and practicing this stuff daily, so bear with me please! I'm a BSME and I want to model up flow between oil filters. Currently we use a single oil filter with the same pump...
  28. Y

    How did Copernicus get the idea of the heliocentric model?

    The heliocentric model marked the beginning of modern astronomy. But what were the reasons which led Copernicus to think that the Earth orbited the sun. I've read that his model was based on observations made by some other astronomer. Can anyone describe how he got this idea?
  29. I

    Kronig-Penney Model in Reciprocal Space

    Homework Statement (a) For the delta-function potential and with P<<1, find at k=0 the energy of the lowest energy band. (This is part A of Charles Kittel Solid State Physics problem 7.3) Homework Equations (P/Ka)sin(Ka)+cos(Ka)=cos(ka) (note, K and k are different variables) ε=\hbar...
  30. U

    Flipping state: Metropolis in Ising model

    Homework Statement Hi everyone, I'm having some difficulties with my code: 1. Randomly Choose a lattice at position (x, y) within the NxN lattice 2. Why by writing "int x = int(drand48()*L);" and "int y = int(drand48()*L);" it doesn't extract the value stored at that location (x, y)? 3...
  31. T

    Bohr Model of the Hydrogen atom: Prove that Eo = 13.6 eV

    Homework Statement Verify that the equation of the ground state energy Eo of the Bohr atom: Eo= (2pi2e4mek2)/h2 simplifies to Eo = 13.6 eV. Show clearly how the units of the different quantities in the equation simplify to the eV. This is all they give. Nothing more...
  32. S

    Does BICEP2's observation rules out ekpyrotic cosmological model ?

    Dear every specialists, I heard that BICEP2's observation r=A_t/A_s=0.2 n_t=0 indicate two things: 1) n_t=0 excludes ekpyrotic cosmological model (ECM) definitely because ECM predicts n_t=2 2) r=0.2 excludes almost all current string inflation model (SIM) such as KKLMMT because this...
  33. J

    Coverting Simple Harmonic Motion Equation to a Rotational Model

    Hi I am using Simple Harmonic Motion in a Matlab/Simulink model. Instead of using a motion for a simple pendulum, I decided to use a spring with a mass. The reasons for this is because my example is more like a lever attached to a pivot point and having an object at the end with a mass. A...
  34. C

    The Hot Big Bang Model and supporting evidence

    Homework Statement I'm having a slightly hard time with a topic we are studying at school 'the evolution of the universe'. My first question relates to the Big Bang Model itself; does the Big Bang Model itself describe the evolution of the universe after the Planck time up to this point...
  35. B

    Single particle shell model for nucleus

    Homework Statement Predict the ground state spin and parity for ^{7}_{3}Li, ^{15}_{7}N. ^{31}_{15}P. Homework Equations Fill up shells for neutrons and protons separately. Shells in increasing energy are: 1S_{1/2}, 1P_{3/2}, 1P_{1/2}, 1S_{1/2}, 1D_{5/2}, 1D_{3/2} and have...
  36. P

    First passage time for Kinetic Monte Carlo model

    Hi all! I have a problem on finding the first passage time for kinetic monte carlo model. Suppose I have a linear kinetic model for n states: S1<->S2<->S3<->...<->Sn where all the rate constants k_ij for transition between any two states are known. Is there any general way to find out the...
  37. Runei

    What causes the repulsive force in diatomic molecules?

    Hello, I'm working here with a model for a diatomic molecule. The potential is modeled as two finite wells. For a given distance between the wells, the energy of the ground state will be minimized. If you move the "atoms" closer to each other, the energy rises, and if you move them away from...
  38. S

    Regression Analysis on Theoretical Model

    Hi everyone. I'm a graduate student and am struggling with something that may possibly be trivial. So, my research is creating a mathematical model to represent a real system. I have data points from my real system that I want to compare my model to. How do I do a regression analysis and get...
  39. M

    Engineering Op Amp Simple Circuit Model

    Homework Statement Please check attached image. I am doing some op amp practice problems and I came across this problem: I have to find the potential at the inverting input of the simple circuit model of the op amp. The op amp would be a basic inverting amplifier. I have to give the...
  40. M

    Is a model nested with itself before collapsing categorical variables?

    If I have a model with a categorical variable X1=0,1,2,3 and a continuous variable X2 and I have a regression model that includes an interaction between X1 and X2, then I decide I want to collapse X1 into an indicator variable where X1_new=0 if X=0 and X1_new=1 if X>=1, is my new model with an...
  41. V

    How Do Quantum Theory and Software Model Large Atoms Like Iron?

    Hi! One can easily analyze the Hydrogen Atom since it is a two body problem. But how do you apply Quantum Theory to model atoms (such as iron) which are much larger and predict their behaviour in an environment? My guess is that you use statistical mechanics, but I only just started a...
  42. B

    Construct Freefall DE Model for Felix Baumgartner

    Homework Statement One of my classes involves constructing a differential equation to model the freefall of the red bull sky diver Felix Baumgartner. I need to construct the correct differential equation to find v(t) and y(t) at any given time t. As stated above, I need to take the two...
  43. P

    Rate constant and Kinetic model

    Hi everyone, I have a question on the rate constant of a kinetic model(like the one we use in describing chemical reaction). Suppose we have the following model between two states A and B: A--(a)-->B A<--(b)--B where a, b are the rate constant for the transition. So the corresponding...
  44. S

    Model windmill, exhibition stand -

    Hello everyone :) I have a problem which I would love help with, very briefly I am having a model windmill built as an exhibition stand. As it's height is just over 3 metres I am being asked some pretty tough questions by the health and safety team at the show. Specifically "what weight...
  45. T

    What is the maximum input voltage for valid analysis in the BJT hybrid pi model?

    Homework Statement Here is the example along with the solution: What I don't get is what happened to the R_E value. So in this model does it neglect this value? It seems like R_E could be anything and you would still get the same model.I have another question, for this same example, it asks...
  46. kq6up

    Easier Way to Build Spice Models from Old Data Sheets

    I would like to find an easier way to build spice models from old data sheets. Normally one would have to tediously build spread sheet tables from curve traces of these old tubes. However, I was wondering if there is some sort of program that allows one to trace lines over the images, set...
  47. B

    Orbital quantum number in the shell model

    Why isn't the Orbital angular momentum quantum number in the nuclear shell model restricted by the principal quantum number like it is in the atomic shell model? Also, does the principal quantum number even correspond to energy in the shell model?
  48. D

    Maximum Height of model rocket

    Homework Statement A model rocket is launched with an initial velocity of 55 m/s. Its height as a function of time can be modeled by h(t) = -4.9t2 + 55t. Determine the maximum height reached by the rocket.Homework Equations h(t) = -4.9t2 + 55tThe Attempt at a Solution h'(0) = 55, since h'(t) =...
  49. N

    MHB LTL, CTL or TLA for modelling for my model (detailed description inside)?

    Hi, I am currently writing my master thesis and am confronted with specifying and verifying my approach in a temporal logic. I will shortly explain the basic scenario, but feel free to ask for details ;-) Basically I'm wondering which temporal logic would be the best to use in my circumstances...
  50. J

    Finding moments of a 3D model.

    Homework Statement (See pic attachment)Homework Equations Moment/Torque = Force * d (Force arm)The Attempt at a Solution I have so far Mx = Fz * ya My = Fx * za Mz = -Fx * ya How I got these answers is by looking at the cube from the component's axis and whether or not it produces a torque...
Back
Top