Name: thermal equilibrium and the zeroth law
Uploaded: 2025-05-22T09:05:48.000Z
Duration: 1 min 14 s
Channel: JoVE

K12 Standards

Louisiana Student Standards for Science

High School

Chemistry

Energy

HS-PS3-4

Zeroth Law of Thermodynamics

熱力学の第 0 法則は、任意の 2 つの物体が 3 番目の物体と熱平衡状態にある場合、それらも互いに熱平衡状態にあると述べています。
これを実験的に理解するために、3つの異なる温度で水で満たされた3つのビーカーを考えてみましょう。
ビーカーAをBに、ビーカーBをCに接続すると、熱伝達が行われます。
しばらくすると、ビーカーAの水はビーカーBの水と熱平衡に達し、ビーカーBの水はビーカーCの水と平衡に達します。
ビーカーの温度を記録すると、3つのビーカーすべてで均一な温度が観察され、これは熱力学のゼロ法則に対応します。
熱力学の零則の最も重要な応用は、さまざまな種類の温度計です。
体温計を使用して物体の温度を測定すると、体温計は自身の温度を変化させることによって熱平衡を達成します。
したがって、測定された体の温度は、実際には温度計の温度です。

<ol>
	<li>OpenStaxです。(2019). 大学物理学 Vol.2.【Web版】。<a href="https://openstax.org/books/university-physics-volume-2/pages/1-1-temperature-and-thermal-equilibrium"から取得>https://openstax.org/books/university-physics-volume-2/pages/1-1-temperature-and-thermal-equilibrium</a></li>
</ol>

熱力学の第ゼロ法則

実験的に、物体 A が物体 B と平衡状態にあり、物体 B が物体 C の場合、物体 A は物体 C と平衡状態になります。 この推移性の記述は、「熱力学の第 0 法則」と呼ばれます。たとえば、冷たい金属ブロックと熱い金属ブロックは両方とも室温の金属板上に置かれます。 最終的に、コールド ブロックとプレートは熱平衡状態になります。 また、ホットブロックとプレートは熱平衡状態になります。 第 0 法則により、コールド ブロックとホット ブロックも熱平衡状態にあると結論付けることができます。

英国の物理学者ラルフ ファウラーは、1930 年代に「ゼロ」という数を提案しました。 当時、熱力学の第一法則、第二法則、第三法則にはすでに名前と番号が付けられていました。 第 0 法則はめったに述べられていませんでしたが、他の法則よりも前に議論する必要があったため、ファウラーは小さい番号を与えました。

次に、A が温度計である場合を考えてみましょう。 第 0 法則は、A が B と平衡状態にあるときに特定の温度を読み取り、それを C と接触させると、 C とはエネルギーを交換しません。 したがって、温度測定値は変わりません。 言い換えれば、2 つの物体が熱平衡にある場合、それらの温度は同じになります。

実験的に、物体Aが物体Bと平衡状態にあり、物体Bが物体Cと平衡状態にある場合、物体Aは物体Cと平衡状態にある。

Education

JoVE Core

Physics

物理学

Unit 1

ユニット1

Temperature and Heat

温度と熱

KEY TERMS AND CONCEPTS

主要用語と概念

thermal equilibrium and the zeroth law

The zeroth law of thermodynamics explains thermal equilibrium between objects. If object A is in equilibrium with object B, and object B is in equilibrium with object C, then object A is also in equilibrium with object C. This transitive relationship is the key idea behind the law.

A simple example uses metal blocks and a metal plate at room temperature. A cold metal block and a hot metal block are both placed on the plate. Over time, the cold block and the plate reach thermal equilibrium, and the hot block and the plate do too. By the zeroth law, the cold block and the hot block are then also in thermal equilibrium.

The law also helps explain how thermometers work. If a thermometer is in equilibrium with one object and then placed in contact with another object, it will not exchange energy with that object if their temperatures match. Its reading stays the same. In other words, two objects in thermal equilibrium have the same temperature.

The name zeroth law was suggested by British physicist Ralph Fowler in the 1930s. By then, the first, second, and third laws of thermodynamics had already been named. The zeroth law was less often stated, but it had to be discussed before the others, so Fowler gave it the smaller number.

Thermal Equilibrium and the Zeroth Law

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zeroth law of thermodynamics

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key terms and concepts

Learn how the zeroth law of thermodynamics shows that objects in thermal equilibrium have the same temperature and why this matters for thermometers.

Thermal Equilibrium and the Zeroth Law | JoVE K12

physics

JoVE Core 物理学は、運動学、力学、流体力学、静力学、波動、音響などの基礎的な物理学の理論と応用を、簡潔でわかりやすいアニメーション ビデオで紹介します。さらに、科学者の実際のビデオでは、世界中の今日の研究所で行われている古典的および独自の研究実験における関連概念の適用を示しています。

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HS-PS3-6

Thermal Equilibrium and the Zeroth Law

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