STEM与日常科技·英语30篇（5）

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为什么有些彩虹是双层的，而有些不是？

A double rainbow forms when sunlight reflects twice inside raindrops instead of just once.
The second reflection makes the outer arc dimmer and reverses its color order compared to the primary bow.
Because light loses energy with each internal reflection, the secondary rainbow is always fainter than the first.
You can only see a double rainbow when the sun is low and rain fills the sky opposite it.
The dark band between the two arcs, called Alexander’s Dark Band, occurs because no light scatters there.
This phenomenon follows precise optical laws involving refraction, reflection, and dispersion in spherical water droplets.
Unlike artificial rainbows from mist or sprinklers, natural double bows require uniform droplet size and angle alignment.
Photographers often wait for specific cloud gaps to capture both arcs clearly without glare.
Scientists use this effect to calibrate atmospheric sensors that measure droplet distribution in clouds.
Even though rare, double rainbows prove how consistently physics shapes everyday sky phenomena.

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

Even though rare, double rainbows prove how consistently physics shapes everyday sky phenomena. 尽管罕见，双彩虹却印证了物理定律如何一贯塑造日常天空现象。
A double rainbow forms when sunlight reflects twice inside raindrops instead of just once. 双彩虹形成于阳光在雨滴内发生两次反射，而非仅一次。
Photographers often wait for specific cloud gaps to capture both arcs clearly without glare. 摄影师常等待特定云隙出现，以避开眩光、清晰捕捉两道虹弧。

这篇中文题目最接近哪一句？为什么有些彩虹是双层的，而有些不是？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？双彩虹形成于阳光在雨滴内发生两次反射，而非仅一次。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 Some Rainbows Appear Double While Others Don’t How to cook noodles A maths worksheet

Even though rare, double rainbows prove how consistently physics shapes everyday sky phenomena.

Even though rare, double rainbows prove how consistently physics shapes everyday sky phenomena.

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：Even though rare, double rainbows prove how consistently physics shapes everyday sky phenomena.