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Do you ever lie on your back outside on a sunny day? There's so much to see!
你曾在晴天里躺在外面看天吗？我们可以看到很多东西。
There are birds, and airplanes, and maybe even clouds, all way up in a pretty blue sky.
有小鸟、飞机、云彩，所有这些都在蓝天下。
But why is the sky blue? Why not green, or red, or any other color?
当天为什么是蓝的呢？为什么不是绿色、红色，或其他颜色呢？
It all starts with light from our big, bright sun.
这要从我们明亮的大太阳发出的光线说起。
Now, it may not look like it, but the light from the sun is made of all of the colors of the rainbow.
现在，这可能看起来不像它，但是太阳光是由所有的彩虹色组成的。
And you might already know that it takes many colors to make up a rainbow, red, orange, yellow, green, blue, and violet!
你可能已经知道彩虹由很多颜色——红橙黄绿蓝紫构成。
All of the colors of the rainbow are in sunlight, all of the time.
所有的彩虹色一直都包含在太阳光中。
It's just that they're all mixed together, so we don't see them!
因为它们混在了一起，所以我们看不到。
It's kind of like when you're painting and you mix together all the colors.
这和你画画时，把所有的颜色都混在一起有点儿像。
With paint, mixing all the colors makes brown, but when you mix together all the colors of light, you get white light.
画画时，所有颜色混合在一起呈棕色，但所有的光混在一起是白光。
You can actually see the different colors in light sometimes!
你有时也可能会看到光线中的不同颜色。
One way to do it is by using a tool called a prism,
一种方法是使用一种叫棱镜的工具，
which is usually just a specially-shaped piece of glass or plastic.
它只是一种特殊形状的玻璃片或塑料片。
But you can even make a prism out of a glass of water!
你甚至可以用一杯水做一个棱镜。
Prisms bend light in a special way, so that we can see all of the colors that make up light.
棱镜用一种特殊的方法使光发生折射，所以我们能看到组成光线的所有颜色。
So that I shine a bright flashlight into a prism.
我用明亮的手电筒照棱镜，
The rays of light move in a straight line away from the flashlight.
手电筒发出的光沿直线传播。
When the light hits the prism, it separates into lots of different colors, and we have a rainbow.
但当光照到棱镜上时，它散射成很多不同的颜色，变成了彩虹。
So, the light is white when it moves in a straight line until it hits the prism.
所以，光在照到棱镜前直线传播时是白色的。
Then, it bends, and we can see all of colors.
然后，它发生了折射，我们就看到了所有的颜色。
That's a little like what happens to the light from the sun.
这有点儿像阳光的。
Rays of light leave the sun in a straight line, too, as they move through space.
太阳光也是在空间直线传播。
They stay in a straight line until they reach the layer of air that surrounds the Earth.
在它照到地球周围的空气层前一直是直线传播。
Now, the air around the Earth is made of tiny little particles, or pieces, that we can't see. But they're there!
地球周围的空气是由微小粒子构成的，肉眼看不见，但确实存在。
If you try moving your hand back and forth really quickly through the air, you'll feel the air moving past your hand.
如果你在空中来回得挥动手，你会感受到空气的经过。
What you're really feeling is all those little particles!
你感受到的就是微小粒子。
When the rays of light hit these tiny particles of air, they don't just bend, like they did when they hit the prism.
当光线照到这些微小粒子时，它们不会像照到棱镜时发生折射。
The light rays scatter, meaning that they go off in lots of directions, and bounce around.
而是发生散射，这意味着它们会散射到不同的方向，来回反射。
And here's the cool thing, some of the colors scatter more than others.
然后神奇的事发生了，一些颜色比其他颜色散射得多。
What color do you think scatters more?
你认为什么颜色散射得更多？
Right you are, Squeaks! Blue! Blue is one of the colors of light that scatters the most!
你说对了，吱吱！是蓝色。蓝色是散射得最多的光线之一。
So, as light from the sun moves into the air that's way high up, the blue-colored light bounces all over the place in the sky.
所以，当太阳光进入高空时，蓝光就会在天空中到处反射。
So the next time you're outside, don't forget to look up.
所以下次你外出时，别忘了抬头看看天空。
And remember all that has to happen to make the sky blue.
想想天为什么是蓝的。
Thanks for joining us for the SciShow Kids!
感谢你收看儿童科学秀哦。
If you have questions about light, the colour and anything at all, you can leave a comment below.
如果你对光线或颜色等有疑问，可以在下方留言。
Or send us an email to kids@scishow.com!
也可以发邮件到kids@scishow.com。
Thanks, and we'll see you next time! Here at the Fort!
感谢您的收看，我们下周见。沃斯堡等你哦
