A teaching tape for LQ-05, Independent Configurations and Boltzmann Entropy

The locked positions

Demonstrates that the probability is (V/V0)^n only when the points are independent; rigidly locked points give V/V0.

Open LQ-05 with these settings

Where it starts

The settings the tape begins from, under the constant set modern-si-2019. Values are the model's own, not the laboratory control's display: a radius of 5e-7 is half a micrometre.
SettingValue
Number of Particles (n)10
Subvolume Fraction (f)0.5
Sampling Trials (trials)10000

What it changes, and what to expect

  1. A question to answer before the next change

    Ten independent particles in half a volume

    With 10 independent points, W = (1/2)^10 = 1/1024.

    Ten independent points move in the box. At a moment picked at random, what is the chance that all ten are in the left half?

    • About one in two The chance for a single point, unchanged by adding points.
    • About one in twenty The chance falls with n, but only in proportion to it.
    • About one in a thousand Each point independently halves the chance, so ten of them give 1/2^10 = 1/1024.
    The answer this tape's author recorded

    About one in a thousand

    What the author recorded that a reader should see here.
    QuantityExpectedUnder
    W (independent)9.76563 × 10⁻⁴modern-si-2019
  2. Set Number of Particles (n) to 60 changes what the run starts from

    Ten locked particles moving rigidly

    When the 10 points are rigidly locked, W = 1/2.

    What the author recorded that a reader should see here.
    QuantityExpectedUnder
    W (locked)0.5modern-si-2019

These are the values the tape's author recorded, not a result this page computed. Nothing here runs the instrument. Open LQ-05 with these settings: the link opens it with them already in place. Compare what it gives you with what is recorded here. The settings travel in the link and the laboratory reads them as it loads, so without JavaScript it opens at its worked example instead.

What these numbers were recorded under

The identities the recorded values belong to. The same instrument run under a different seed, or under a later version of its model, gives different numbers without either set being wrong.
IdentityRecorded as
Modellq05-independent-configurations-v1 version 1
Seed12345
Random-stream semanticsversion 1

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