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🔊 声速计算器Speed of Sound Calculator
按理想气体公式 v = √(γRT/M) 计算干燥空气中随温度变化的声速，也可选水、钢等介质的典型声速；还能由声音传播时间算距离（例如看到闪电后几秒听到雷声）。Calculate the speed of sound in dry air at any temperature with v = √(γRT/M), or use typical values for water, steel and other media — and turn a delay into a distance, such as the seconds between lightning and thunder.
使用说明与常见问题How-to & FAQ
「声速计算器」是什么？What is the Speed of Sound Calculator tool?
按理想气体公式 v = √(γRT/M) 计算干燥空气中随温度变化的声速，也可选水、钢等介质的典型声速；还能由声音传播时间算距离（例如看到闪电后几秒听到雷声）。Calculate the speed of sound in dry air at any temperature with v = √(γRT/M), or use typical values for water, steel and other media — and turn a delay into a distance, such as the seconds between lightning and thunder.
如何使用「声速计算器」？How do I use the Speed of Sound Calculator tool?
在「声速计算器」中，填写「介质」、「温度单位」、「空气温度」、「声音传播时间 s（可选）」等参数，结果会随输入实时计算并显示在下方。In the Speed of Sound Calculator: Fill in "Medium", "Temperature unit", "Air temperature", "Travel time s (optional)"; results are recalculated instantly as you type.
空气中的声速怎么算？How is the speed of sound in air calculated?
干燥空气视为理想气体：v = √(γRT/M)，γ = 1.4，R = 8.314462618 J/(mol·K)，M = 0.0289645 kg/mol，T 为开尔文温度。0 °C 时约 331.3 m/s，20 °C 时约 343.2 m/s，每升高 1 °C 约增加 0.6 m/s。Dry air is treated as an ideal gas: v = √(γRT/M) with γ = 1.4, R = 8.314462618 J/(mol·K), M = 0.0289645 kg/mol and T in kelvin. That is about 331.3 m/s at 0 °C and 343.2 m/s at 20 °C, rising roughly 0.6 m/s per °C.
怎么用雷声估算闪电距离？How far away is the lightning?
数一数看到闪电到听到雷声的秒数，乘以声速。20 °C 时每 3 秒约 1 公里，每 5 秒约 1 英里。Count the seconds from flash to thunder and multiply by the speed of sound — at 20 °C about 3 seconds per kilometre or 5 seconds per mile.
湿度有影响吗？Does humidity matter?
有轻微影响：潮湿空气中的声速略快，30 °C 饱和湿度时约快 0.5%。本工具按干燥空气计算。Slightly — humid air carries sound a little faster, about 0.5% at 30 °C and full saturation. This tool assumes dry air.
计算结果可以用于作业或工程吗？Can I use the results for homework or engineering?
「声速计算器」使用教科书标准公式（公式写在说明和常见问题中），适合学习和估算核对；涉及安全的工程设计请以规范和实测为准。The Speed of Sound Calculator uses standard textbook formulas (given in the description and FAQ), which is good for learning and checking estimates; for safety-critical engineering follow codes and measured values.
「声速计算器」免费吗？需要注册吗？Is the Speed of Sound Calculator free? Do I need an account?
「声速计算器」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Speed of Sound Calculator is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.