【英语时差8,16】灯泡和鸡蛋

A Light Bulb And An Egg What a light bulb and an egg have in common? The shell of an egg and the glass exterior¹ of a light bulb have more than one thing in common. First, both protect something delicate inside: the exterior of the light bulb keeps the delicate internal wiring protected and an eggshell protects a developing chick. The need to protect chicks and wiring requires that eggshells and light bulbs be structurally² strong. Second, both are made of thin material. A chick, ready to hatch, has to be able to peck its way through the shell. And because light bulbs are usually made of opaque³ rather than clear glass, the glass exterior must be thin so that light can shine through. So how can a structure be strong and yet made of thin material at the same time? By using a carefully-designed oval shape. Picture for a moment a square egg. If you took that imaginary object in your hand and squeezed it very hard between your thumb and finger, the pressure you’d exert would be localized in the exact part of the flat surface your thumb and finger were pushing. Even a slight pressure would be great enough to break the thin shell into pieces. But if you do the same thing to a real egg, the force you exert is not localized in one point, but is distributed into all directions around the surface of the egg. Though you can eventually break an egg by doing this, it takes a great deal more force to do so. Of course, it’s no coincidence that the shapes of light bulbs and eggs are similar. When the light bulb was invented and perfected, it was patterned after a shape that nature had come up with hundreds of thousands of years ago.

1 exterior   

adj.外部的，外在的；表面的

参考例句：

• The seed has a hard exterior covering.这种子外壳很硬。
• We are painting the exterior wall of the house.我们正在给房子的外墙涂漆。

2 structurally   

在结构上

参考例句：

• The house roof was (structurally) unsound. 这屋顶（结构）不牢固。
• Pinhole on shot-hole damage is never structurally significant. 针孔和蛀洞所造成的危害对结构的影响不大。

3 opaque   

adj.不透光的；不反光的，不传导的；晦涩的

参考例句：

• The windows are of opaque glass.这些窗户装着不透明玻璃。
• Their intentions remained opaque.他们的意图仍然令人费解。