科学为什么·英语30篇（1）

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为什么某些火山灰云能飘行数千公里而不沉降？

Volcanic ash consists of tiny, jagged rock and glass particles blasted into the atmosphere during eruptions.
When ejected above 10 km, ash enters the stratosphere where winds blow steadily and there’s little rain.
Particles smaller than 0.063 mm can stay airborne for weeks because gravity pulls them down very slowly.
Electrostatic forces sometimes keep ash grains apart, preventing clumping and faster fall.
Sunlight heats ash layers unevenly, creating small updrafts that temporarily lift particles higher.
Jet streams then carry fine ash across continents before weak turbulence finally brings it down.
Scientists track ash using satellites that detect infrared signatures distinct from normal clouds.
Airline routes often change because ash melts inside jet engines and damages turbine blades.
Unlike dust storms, volcanic ash contains sharp minerals that resist weathering mid-air.
Its global spread proves how interconnected Earth’s atmospheric systems truly are.

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

Its global spread proves how interconnected Earth’s atmospheric systems truly are. 其全球扩散印证了地球大气系统真正的紧密关联性。
Electrostatic forces sometimes keep ash grains apart, preventing clumping and faster fall. 静电作用有时使灰粒相互排斥，阻止团聚，延缓下落。
Unlike dust storms, volcanic ash contains sharp minerals that resist weathering mid-air. 与沙尘暴不同，火山灰含尖锐矿物，空中不易风化。

这篇中文题目最接近哪一句？为什么某些火山灰云能飘行数千公里而不沉降？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？火山灰由火山喷发时抛入大气的微小、棱角分明的岩石和玻璃颗粒组成。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 Some Volcanic Ash Clouds Travel Thousands of Kilometers Without Settling? How to cook noodles A maths worksheet

Its global spread proves how interconnected Earth’s atmospheric systems truly are.

Its global spread proves how interconnected Earth’s atmospheric systems truly are.

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：Its global spread proves how interconnected Earth’s atmospheric systems truly are.