Name: kelvin temperature and gas thermometer standards
Uploaded: 2023-04-30T12:29:16.000Z
Duration: 1 min 22 s
Channel: JoVE

K12 Standards

Texas Essential Knowledge and Skills

High School

Chemistry

CHEM.13

CHEM.13.D

Gas Thermometers and the Kelvin Scale

가스 온도계는 가스가 채워진 압력이나 부피의 변화를 기반으로 온도를 평가합니다.
가스 온도계에는 일정 부피와 일정 압력의 두 가지 유형이 있으며 일정 부피 가스 온도계가 가장 널리 사용됩니다.
이 온도계의 원리는 일정한 부피에서 온도가 증가함에 따라 가스의 압력이 증가한다는 것입니다.
가스 온도계를 보정하기 위해 섭씨 0도 및 100도의 압력을 측정합니다.
이러한 값은 직선으로 표시되며, 이는 제로 압력 온도를 찾기 위해 외삽됩니다.
이 온도는 켈빈 척도의 영점입니다. 온도의 SI 단위가 켈빈이므로 이것은 온도의 표준 척도입니다.
절대 영도는 열 에너지가 전혀 없음을 이상적으로 반영하는 가능한 가장 낮은 온도입니다.
켈빈 척도에서 물의 어는점은 273.15이고 끓는점은 373.15입니다. 차이는 섭씨 눈금과 동일합니다. 영점만 다릅니다.
따라서 켈빈과 섭씨 눈금 사이의 관계를 쉽게 설정할 수 있습니다.

<ol>
	<li>오픈스택스. (2019). 대학 물리학 Vol. 2. [웹 버전]. 원본 주소 <a href="https://openstax.org/books/university-physics-volume-2/pages/1-2-thermometers-and-temperature-scales">https://openstax.org/books/university-physics-volume-2/pages/1-2-thermometers-and-temperature-scales</a></li>
</ol>

가스 온도계와 켈빈 척도

분자 운동 측면에서 온도를 정의하면 분자의 평균 운동 에너지가 0(또는 양자역학에서 허용하는 최소값)이 되는 가장 낮은 온도가 있어야 함을 시사합니다. 실험을 통해 절대 영도라고 불리는 온도의 존재가 확인되었습니다. 절대 온도 눈금은 영점이 절대 영도인 눈금입니다. 이러한 저울은 이상 기체의 부피와 같은 여러 물리적 양이 절대 온도와 직접적인 관련이 있기 때문에 과학에서 편리합니다.

켈빈 척도는 과학에서 일반적으로 사용되는 절대 온도 척도입니다.

켈빈 척도는 SI 단위계의 일부이므로 실제 정의는 위에 제시된 것보다 더 복잡합니다. 첫째, 물의 어는점과 끓는점으로 정의되는 것이 아니라 삼중점으로 정의됩니다. 삼중점은 얼음, 액체 물, 수증기가 안정적으로 공존할 수 있는 온도와 압력의 독특한 조합입니다. 삼중점 온도는 273.16K로 정의됩니다. 이 정의는 물의 어는 온도와 끓는 온도가 압력에 따라 달라지지만 삼중점 온도는 하나만 있다는 장점이 있습니다.

눈금 위에 잘 정의된 지점이 있더라도 다른 온도계는 다른 온도에 대해 다소 다른 결과를 제공합니다. 따라서 표준 온도계가 필요합니다. 계측학자들은 이러한 목적으로 정량 가스 온도계를 선택했습니다. 가스로 채워진 일정한 부피의 용기에 온도 변화가 생기고 측정된 온도는 압력 변화에 비례합니다. 결과는 가스 선택에 따라 어느 정도 달라지지만 전구의 가스 밀도가 낮을수록 다양한 가스에 대한 결과가 더 잘 일치합니다. 결과를 밀도 0으로 외삽하면 결과는 매우 잘 일치하며 절대 온도 0에 해당하는 압력 0이 됩니다. 정부적 가스 온도계는 크기가 크고 평형에 도달하는 속도가 느리기 때문에 주로 다른 온도계를 교정하는 표준으로 사용됩니다.

분자 운동 측면에서 온도의 정의는 평균 운동 에너지가 ...

Education

교육

JoVE Core

Physics

물리학

Unit 1

제1단원

Temperature and Heat

온도와 열

KEY TERMS AND CONCEPTS

주요 용어 및 개념

kelvin temperature and gas thermometer standards

Kelvin temperature is the absolute scale used in science, and it starts at absolute zero. That zero point matches the lowest possible temperature, where molecular motion reaches zero or the minimum allowed by quantum mechanics. Scientists use this scale because some physical quantities, such as the volume of an ideal gas, depend directly on absolute temperature.

The Kelvin scale is part of the SI system of units, so its definition is more precise than simply using water’s freezing and boiling points. Instead, it is tied to the triple point of water. The triple point is the only temperature and pressure combination where ice, liquid water, and water vapor can all coexist. Its temperature is defined as 273.16 K, which is useful because it does not change with pressure the way water’s freezing and boiling points do.

Even with fixed reference points, different thermometers can give slightly different readings for other temperatures. For that reason, scientists need a standard thermometer. Metrologists use the constant-volume gas thermometer for this job. In this device, a gas in a sealed vessel stays at the same volume while temperature changes, and the temperature is found from the change in pressure.

The choice of gas can affect the results a little. However, the less dense the gas in the bulb, the better different gases agree. When the results are extrapolated to zero density, they match well, and zero pressure corresponds to absolute zero. Constant-volume gas thermometers are large and slow to reach equilibrium, so they are mainly used as standards to calibrate other thermometers.

Kelvin Temperature and Gas Thermometer Standards

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gas thermometers and the kelvin scale

Kelvin temperature is the absolute scale used in science, and it starts at absolute zero. That zero point matches the lowest possible temperature, where molecular motion reaches zero or the minimum allowed by quantum mechanics. Scientists use this scale because some physical quantities, such as the volume of an ideal gas, depend directly on absolute temperature. The Kelvin scale is part of the SI system of units, so its definition is more precise than simply using water’s freezing and boiling...

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Radiation heat transfer depends on temperature, surface area, and emissivity. The Stefan-Boltzmann law describes the rate of heat transfer by emitted radiation. In this law, σ is the Stefan-Boltzmann constant, A is the object’s surface area, and T is its temperature in kelvins. The fourth-power dependence on absolute temperature makes radiation highly sensitive to small temperature changes. Even a slight rise in temperature can change the emitted heat a lot. That sensitivity is why radiation...

key terms and concepts

Learn how the Kelvin scale is tied to absolute zero, the triple point of water, and constant-volume gas thermometers used to calibrate other thermometers.

Kelvin Temperature and Gas Thermometer Standards | JoVE K12

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Kelvin Temperature and Gas Thermometer Standards

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