时差N小时 你知道保鲜膜的原理吗?(下)

Now that you know the secret to plastic wrap’s elasticity¹, let’s explore why it’s sticky.

既然你已经知晓保鲜膜弹性的原理了，现在就探究下保鲜膜的粘性吧。

Most thin plastic films easily pick up a static electric charge by friction².

大多数保鲜薄膜均可通过摩擦获得静电荷。

In other words, plastic wrap is static electricity waiting to happen.

也就是说，保鲜膜随时会产生静电。

As you pull the plastic wrap from the roll, or as it brushes against your sleeve, the friction could cause electrons to be displaced onto one area of the plastic, giving it a negative charge.

当你从卷筒中抽出保鲜膜，或保鲜膜轻擦过衣袖时，摩擦导致电子转移到保鲜膜的某一区域，该区域因此产生负电荷。

The surface that lost the electrons would then have a positive charge.

而失去电子的表面会产生正电荷。

Since opposites attract, the plastic wrap and any oppositely charged surface, whether that’s the plate of food,

由于异性相吸，不论是装有食物的盘子、

your sleeve, or even another part of the plastic wrap itself, will cling to each other by electrical attraction.

衣袖甚至保鲜膜的其它部分，保鲜膜都会因为电荷间的相互吸引而与之贴合在一起。

1 elasticity   

n.弹性，伸缩力

参考例句：

• The skin eventually loses its elasticity.皮肤最终会失去弹性。
• Every sort of spring has a definite elasticity.每一种弹簧都有一定的弹性。

2 friction   

n.摩擦，摩擦力

参考例句：

• When Joan returned to work,the friction between them increased.琼回来工作后，他们之间的摩擦加剧了。
• Friction acts on moving bodies and brings them to a stop.摩擦力作用于运动着的物体，并使其停止。