There are three parts in most airline windows.

大部分的飛機窗有三層。

First is the inner layer, which is the dust or scratch cover. It keeps people from poking or scratching the real window.

首先是最內層，又稱防塵蓋或防刮蓋。它被用來避免乘客從機艙內部刮傷真正的飛機窗。

Behind that are two other panes that make up the main part of the window.

在它後面的兩片隔板則是組成飛機窗的主要部分。

They're two, half-inch thick pieces of plexiglass, and they're separated by about a half an inch of air.

它們是兩片半英寸厚的塑膠玻璃，中間隔著約半英寸的氣隙。

The middle pane has that hole. It's sometimes called the breather hole.

小洞就位在中間隔板，有時也被稱做呼吸孔。

There are two purposes for the hole.

它有兩個作用。

One, the hole lets warm air in between the 2 panes keeping the outer window from getting frosted or fogged up from the really cool air outside.

一，小孔可以讓暖空氣流進兩隔板之間，讓最外層隔板不會因為機艙外的冰冷空氣而起霧或結霜。

Two, when the plane ascends and descends, the air pressure on the window changes.

其次，飛機起降時氣壓會不斷在飛機窗中變化。

That little breather hole keeps the pressure inside those two panes the same, so they don't implode or explode. That's what the hole is for!

這個小孔可讓在兩個隔板間保持一致，才不會因此內爆或外爆。而這就是這個小孔的功能！