十万个为什么·科学启蒙30篇（3）

6 / 30

已读 0 / 30 课

彩虹是怎么出现的

A rainbow appears when sunlight enters a raindrop, bends, reflects off the back, and bends again while exiting.
Each color of light bends by a slightly different amount, separating white light into its full spectrum.
Red light bends the least and exits at about 42 degrees, while violet bends the most at 40 degrees.
Your eyes see red higher in the arc and violet lower because of these precise exit angles.
You must stand with your back to the Sun and face falling rain to see a rainbow at all.
The center of the rainbow’s circle lies directly opposite the Sun from your viewpoint.
Double rainbows happen when light reflects twice inside the drop, reversing the color order in the outer bow.
Rainbows are not physical objects—they exist only where light, raindrops, and your eyes align perfectly.
Fogbows look white because tiny fog droplets scatter light too broadly to separate colors clearly.
At sunrise or sunset, the Sun’s low angle can make rainbows appear fuller and more vivid.

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

The center of the rainbow’s circle lies directly opposite the Sun from your viewpoint. 彩虹所在圆的圆心，恰好位于你视线中太阳的正对面。
Rainbows are not physical objects—they exist only where light, raindrops, and your eyes align perfectly. 彩虹并非实体——它只存在于光线、雨滴与你的眼睛完美对齐的位置。
Fogbows look white because tiny fog droplets scatter light too broadly to separate colors clearly. 雾虹呈白色，因为微小的雾滴散射太强，无法清晰分离出各色光。

这篇中文题目最接近哪一句？彩虹是怎么出现的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？彩虹形成于阳光射入雨滴后发生折射、在雨滴内壁反射，再折射而出的过程。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） How Does a Rainbow Form? How to cook noodles A maths worksheet

The center of the rainbow’s circle lies directly opposite the Sun from your viewpoint.

The center of the rainbow’s circle lies directly opposite the Sun from your viewpoint.

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：The center of the rainbow’s circle lies directly opposite the Sun from your viewpoint.