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

K12 Standards

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High School

Chemistry

Energy

HS-PS3-4

Zeroth Law of Thermodynamics

Der nullte Hauptsatz der Thermodynamik besagt, dass, wenn sich zwei beliebige Körper im thermischen Gleichgewicht mit einem dritten Körper befinden, sie sich auch im thermischen Gleichgewicht miteinander befinden.
Um dies experimentell zu verstehen, betrachten Sie drei Becher, die mit Wasser bei drei verschiedenen Temperaturen gefüllt sind.
Nach dem Verbinden von Becherglas A mit B und Becherglas B mit C findet die Wärmeübertragung statt.
Nach einer gewissen Zeit erreicht das Wasser in Becherglas A ein thermisches Gleichgewicht mit dem Wasser in Becher B, und das Wasser in Becherglas B erreicht ein Gleichgewicht mit dem Wasser in Becherglas C.
Bei der Aufzeichnung der Temperatur der Becher wird in allen drei Bechern eine gleichmäßige Temperatur beobachtet, die dem nullten Hauptsatz der Thermodynamik entspricht.
Die bedeutendste Anwendung des nullten Hauptsatzes der Thermodynamik sind die verschiedenen Arten von Thermometern.
Wenn ein Thermometer verwendet wird, um die Temperatur eines Körpers zu messen, erreicht es ein thermisches Gleichgewicht, indem es seine eigene Temperatur ändert.
Die gemessene Temperatur des Körpers ist also tatsächlich die Temperatur des Thermometers.

<ol>
	<li>OpenStax. (2019). Universitätsphysik Vol. 2. [Webversion]. Abgerufen von <a href="https://openstax.org/books/university-physics-volume-2/pages/1-1-temperature-and-thermal-equilibrium">https://openstax.org/books/university-physics-volume-2/pages/1-1-temperature-and-thermal-equilibrium</a></li>
</ol>

das nullte gesetz der thermodynamik

Wenn, experimentell gesehen, Objekt A im Gleichgewicht mit Objekt B steht und Objekt B im Gleichgewicht mit Objekt C steht, dann steht Objekt A im Gleichgewicht mit Objekt C. Diese Aussage der Transitivität wird das "nullte Gesetz der Thermodynamik" genannt. Werden beispielsweise ein kalter Metallblock und ein heißer Metallblock beide auf einer Metallplatte bei Raumtemperatur platziert, dann werden sich der kalte Block und die Platte schließlich im thermischen Gleichgewicht befinden. Zusätzlich werden der heiße Block und die Platte im thermischen Gleichgewicht sein. Durch das nullte Gesetz können wir schlussfolgern, dass der kalte Block und der heiße Block auch im thermischen Gleichgewicht sind.

Der britische Physiker Ralph Fowler schlug in den 1930er Jahren die Bezeichnung "nulltes" vor. Zu dieser Zeit waren bereits das erste, zweite und dritte Gesetz der Thermodynamik benannt und nummeriert. Das nullte Gesetz war selten genannt worden, aber es musste vor den anderen diskutiert werden, also gab Fowler ihm eine kleinere Nummer.

Betrachten wir nun den Fall, in dem A ein Thermometer ist. Das nullte Gesetz besagt, dass wenn A eine bestimmte Temperatur abliest, wenn es im Gleichgewicht mit B steht, und es dann mit C in Kontakt gebracht wird, keine Energie mit C austauscht. Daher bleibt die Temperaturanzeige gleich. Mit anderen Worten, wenn zwei Objekte im thermischen Gleichgewicht sind, haben sie die gleiche Temperatur.

Das Nullte Gesetz der Thermodynamik

Experimentell, wenn Objekt A mit Objekt B im Gleichgewicht ist und Objekt B im Gleichgewicht mit Objekt C, dann befindet sich Objekt A im Gleichgewicht mit Objekt C. ...

Education

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Unit 1

Einheit 1

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KEY TERMS AND CONCEPTS

KERNBEGRIFFE UND KONZEPTE

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

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...

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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

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HS-PS3-6

Thermal Equilibrium and the Zeroth Law

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