温度

概述

温度测量系统中粒子的平均动能，并决定e direction of heat flow — heat always moves from a warmer body to a cooler one until equilibrium is reached.

工程中使用四种温标：

• 摄氏度 (°C) — 公制温标；标准压力下水在 0 °C 结冰、100 °C 沸腾ressure.
• 华氏度 (°F) — 美国习惯温标；水在 32 °F 结冰、212 °F 沸腾。
• 开尔文 (K) — 绝对公制温标；零开尔文等于绝对零度 (−273.15 °C)。o degree symbol is used.
• 兰金度 (°R) — 绝对英制温标；零兰金度等于绝对零度 (−459.67 °F)F).

绝对零度是温度的理论下限，为 0 K（−273.15 °C、−459.67 °F） °F, 0 °R). All molecular motion ceases at this point.

关键公式

Celsius ↔ Fahrenheit

$T(°F) = 1.8 \times T(°C) + 32$

$T(°C) = \frac{T(°F) - 32}{1.8}$

Celsius ↔ Kelvin

$T(K) = T(°C) + 273.15$

$T(°C) = T(K) - 273.15$

Rankine ↔ Other Scales

$T(°R) = T(°F) + 459.67$

$T(°R) = 1.8 \times T(K)$

Temperature Difference

Temperature differences convert with a scale factor only — no offset:

$\Delta T(°F) = 1.8 \times \Delta T(°C)$

$\Delta T(°R) = 1.8 \times \Delta T(K)$

$\Delta T(K) = \Delta T(°C)$

Example: Water cooled from 100 °C to 60 °C. The difference is ΔT = 40 °C = 72 °F (not 140 °F − 104 °F without the offset). In Fahrenheit: ΔT = 1.8 × 40 = 72 °F.

变量

Four-Scale Conversion Table

Celsius ↔ Fahrenheit Reference

Celsius ↔ Fahrenheit Converter

Four-Scale Temperature Converter

The original source converter is restored here with Celsius, Fahrenheit, Kelvin, and Rankine outputs in one calculator.

Related Mobile App from The Engineering ToolBox

The original page promoted adding the temperature converter web app to mobile devices. That content is preserved as the migrated web-app note: the temperature converter can be used as a browser-based calculator on phones and tablets for quick Celsius, Fahrenheit, Kelvin, and Rankine conversions without installing a separate native application.

还原的原始源表

以下表格还原自原始来源页面，以保留完整的参考数据。

Temperature Units

Celsius vs. Fahrenheit

原始源图

以下原始来源图像予以保留，以免丢失视觉参考资料。当图像包含图表或表格数据时，其提取值已呈现在页面的表格、计算器或交互式图表中；其余图像保留为视觉来源参考。

工程要点

• Notation convention: Use °C for an absolute temperature reading and C° for a temperature difference. For example, a rise from 20 °C to 50 °C is a 30 C° change. The same change equals 54 °F or 54 °R difference.
• Scale increments: 1 K = 1 C° = 1.8 °F = 1.8 °R. The Celsius and Kelvin scales share the same degree size; Fahrenheit and Rankine share the same (smaller) degree size.
• Rankine usage: The Rankine scale appears mainly in legacy US aerospace and power-cycle thermodynamic calculations. Modern international work uses Kelvin.
• Practical limits: While absolute zero is the theoretical floor, the cosmic microwave background sets a natural ambient temperature of about 2.7 K. Most engineering materials change properties significantly below −40 °C, where the Celsius and Fahrenheit scales happen to intersect (−40 °C = −40 °F).
• Precision: When converting between scales, carry extra decimal places through intermediate steps to avoid rounding errors in derived calculations such as heat transfer or efficiency.

参考资料

• Temperature — Engineering ToolBox