十万个为什么·科学阅读30篇（1）

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为什么盐能融化道路结冰却不能融化湖面厚冰？

Salt lowers water’s freezing point, so ice melts when salt dissolves into surface moisture.
On roads, thin ice layers mix easily with salt, forming brine that spreads and accelerates melting.
Frozen lakes have thick, dense ice with little surface liquid—so salt cannot dissolve effectively.
Without liquid water to carry ions, salt crystals just sit on top without triggering melting.
Wind, sunlight, and traffic help road salt work faster, but lakes lack those factors.
Even large amounts of salt won’t melt deep lake ice because heat transfer is too slow.
Scientists measure ‘eutectic temperature’—the lowest point where saltwater stays liquid—at -21°C.
Below that, salt stops working entirely, regardless of quantity or mixing.
In nature, only shallow ponds or icy puddles respond well to small salt doses.
That’s why winter safety teams never use salt on frozen rivers or lakes.

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Scientists measure ‘eutectic temperature’—the lowest point where saltwater stays liquid—at -21°C. 科学家测定‘共晶温度’——盐水保持液态的最低温度为-21°C。
Below that, salt stops working entirely, regardless of quantity or mixing. 低于该温度，无论盐量多少或是否搅拌，盐都完全失效。
That’s why winter safety teams never use salt on frozen rivers or lakes. 因此冬季安全团队从不在结冰的河流或湖泊上使用盐。

这篇中文题目最接近哪一句？为什么盐能融化道路结冰却不能融化湖面厚冰？一次学校运动会的通知一份超市购物清单

课文第一句的意思更接近？盐能降低水的冰点，因此盐溶解在冰面水分中时，冰就会融化。今天学校放假了。请把窗户打开。

这一课主要在讲什么？（看英文标题） Why Does Salt Melt Ice on Roads But Not on Frozen Lakes? How to cook noodles A maths worksheet

Scientists measure ‘eutectic temperature’—the lowest point where saltwater stays liquid—at -21°C.

Scientists measure ‘eutectic temperature’—the lowest point where saltwater stays liquid—at -21°C.

第一版：录下来、回听、再听标准音。系统打分以后再加。

用今天的表达，自己说一句。

例子：Scientists measure ‘eutectic temperature’—the lowest point where saltwater stays liquid—at -21°C.