十万个为什么·科学启蒙30篇（2）

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为什么冰刀能在冰面上顺畅滑行？

Ice skates glide smoothly because pressure from the blade melts a thin layer of ice.
This melted water acts like a lubricant between the skate and the ice surface.
Although the air is cold, the localized pressure lowers the melting point of ice.
The water refreezes instantly once the skate moves away and pressure drops.
That’s why skating feels almost frictionless when done correctly and steadily.
Scientists once thought friction heat caused all the melting, but now know pressure plays a bigger role.
Even at temperatures far below freezing, this effect still works under enough pressure.
The smoother and sharper the blade, the more evenly it distributes pressure on the ice.
Skaters lean slightly to control direction by changing where pressure is applied.
Understanding this helps engineers design better blades and safer rinks.

听 → 读 → 学表达 → 懂 → 今天会说这一句 → 跟读录音 → 自己说一句。

Understanding this helps engineers design better blades and safer rinks. 理解这一原理有助于工程师设计更优的冰刀和更安全的冰场。
That’s why skating feels almost frictionless when done correctly and steadily. 因此，正确而平稳地滑行时，几乎感觉不到摩擦力。
The water refreezes instantly once the skate moves away and pressure drops. 冰刀移开、压力消失后，水会瞬间重新结冰。

这篇中文题目最接近哪一句？为什么冰刀能在冰面上顺畅滑行？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？冰刀能顺畅滑行，是因为刀刃施加的压力使表层冰融化成一层薄水。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 Do Ice Skates Glide Smoothly on Ice? How to cook noodles A maths worksheet

Understanding this helps engineers design better blades and safer rinks.

Understanding this helps engineers design better blades and safer rinks.

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：Understanding this helps engineers design better blades and safer rinks.