Take a look out your window, put on your glasses if you wear them.
向窗外张望一下，有必要的话，戴上眼镜。
You might want to grab a pair of binoculars, too, or a magnifying lens.
也许你还想拿副望远镜或是放大镜。
Now, what do you see?
现在，你看到了什么
Well, whatever it is, it's not the multiple layers of glass right in front of you.
无论你看到了什么答案，都可能不是那一层层近在咫尺的玻璃。
But have you ever wondered how something so solid can be so invisible?
但是你是否想知道，为什么有如此固态的东西却看不见呢？
To understand that, we have to understand what glass actually is, and where it comes from.
要明白这点，我们首先要知道玻璃究竟是什么，以及它是怎样形成的。
It all begins in the Earth's crust, where the two most common elements are silicon and oxygen.
所有一切都始于地壳在它其中最基本的两种元素：硅和氧。
These react together to form silicon dioxide, whose molecules arrange themselves into a regular crystalline form known as quartz.
它们相互作用形成二氧化硅，二氧化物的分子自动排列形成晶体状物，被称为石英。
Quartz is commonly found in sand, where it often makes up most of the grains and is the main ingredient in most type of glass.
石英通常在沙中被发现，沙大多由颗粒组成，而颗粒是多数玻璃的主要原料。
Of course, you probably noticed that glass isn't made of multiple tiny bits of quartz, and for good reason
当然，你可能注意到玻璃并不是由许多石英粒组成的，这点显而易见。
For one thing, the edges of the rigidly formed grains and smaller defects within the crystal structure reflect and disperse light that hits them
一方面，晶体结构内部严格形成的颗粒边缘或者很小的瑕疵反射及散射照向它们的光。
But when the quartz is heated high enough the extra energy makes the molecules vibrate until they break the bonds holding them together and become a flowing liquid, the same way that ice melts into water.
但是当石英加热到足够热时，产生的热量就会让分子产生震动直到它们打破以前的链结，进而形成流动的液体，就和冰融化成水一样。
Unlike water, though, liquid silicon dioxide does not reform into a crystal solid when it cools
但是和水不同的是，液态的二氧化硅冷却之后不会形成固态晶体。
Instead, as the molecules lose energy, they are less and less able to move into an ordered position, and the result is what is called an amorphous solid.
相反，当分子失去能量后，它们就更不太可能移动形成一个有秩序的状态，这样的结果就是人们所说的非晶型固体。
A solid material with the chaotic structure of a liquid, which allows the molecules to freely fill in any gaps.
一种具有混乱液体结构的固态物质使得分子可以自由填补任何缝隙。
This makes the surface of glass uniform on a microscopic level, allowing light to strike it without being scattered in different directions.
这样就让玻璃表面在微观层面上是一致的，光可以穿透它但不会散射出去。
