• Pixel-art sticker of Clausor, personifying Entropy Change, with the caption “Same Heat, Cold Gets More.”

IndexHeat & EntropySticker

Clausor

Entropy Change Physics

\[\Delta S = \frac{Q}{T}\]
$4.99 USD
$4.99 USD
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Meet Clausor, an ice cube who gains more entropy from a little heat than a hot coal does. Entropy change is heat over kelvin temperature: 1000 J adds 3.66 J/K at 273 K but only 2.68 J/K at 373 K. So heat flowing hot to cold raises total entropy. Pixel-art kiss-cut sticker in 2, 3, 4 and 6 inches; equation, symbols and sources in the physics panel below.

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Flat $6 shipping worldwideMade to order, ships in 2–5 business days

Details

Size3″ × 3″

3″ × 3″ kiss-cut sticker.

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Returns & replacements21 days

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The physics

Meet Clausor, an ice cube who gains far more entropy from a little heat than a hot coal does.

Entropy measures how many ways energy can be spread among the particles in something. When heat Q flows into an object at a steady temperature T, its entropy rises by ΔS = Q/T, with T in kelvin.

Give 1000 J to ice melting at 273 K and its entropy rises by about 3.66 J/K. Give the same 1000 J to something at 373 K and it rises by only about 2.68 J/K. Cold things gain more from the same heat.

So when 1000 J flows from the hot object to the cold one, the hot one loses 2.68 J/K but the cold one gains 3.66 J/K. Total entropy goes up by about 0.98 J/K.

That is the second law of thermodynamics. Heat flows on its own from hot to cold because that direction always increases the total entropy.

Equations

\[\Delta S = \frac{Q}{T}\]
SymbolMeaningUnit
\(\Delta S\) change in entropy \(\mathrm{J/K}\)
\(Q\) heat added \(\mathrm{J}\)
\(T\) absolute temperature \(\mathrm{K}\)

Sources

  1. OpenStax University Physics Vol. 2 — Entropy
  2. Wikipedia — Entropy (classical thermodynamics)

Field notes

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