听力文摘第316期:千层面的怨念

So you made lasagna last night, and it was delicious.

你昨晚做了千层面，而且非常美味。

You saved the leftovers¹ by wrapping aluminum² foil over the top of the pan, and putting it in the fridge.

你将剩下的千层面用铝箔纸包好放入冰箱中。

When you get hungry today, you go to look for that lasagna, but it looks like the lasagna was getting hungry too!

今天你饿的时候，便去拿昨天吃剩的千层面，但是你会发现千层面似乎也饿了！

It's eaten tiny holes in the aluminum foil that was covering it.

包裹它的铝箔纸上出现了一个个的小洞，好像被咬过一样。

Why does this happen?

为什么会这样呢？

A listener asked this question and we'll find the answer on today's moment of science.

一位听众问到了这个问题，我们将在今天的科学一刻中为你解答。

千层面.jpg

There are really two things responsible for those holes in the aluminum foil: the acidic nature of the lasagna and some curious properties of aluminum.

铝箔上出现这些洞有两个原因：一个是千层面本身具有酸性，另一个就是铝具有一些非常奇特的属性。

Lasagna gets most of it's acid from the tomatoes in its sauce.

千层面的酸性主要是来自酱汁中的番茄酱。

Almost everything you eat is at least slightly acidic, but tomatoes are especially so.

几乎你吃的每样东西都会至少呈轻微酸性，而番茄的酸性尤为明显。

This acid wouldn't be a problem for a glass container, or stainless³ steel, or plastic wrap, or for most of the materials we use to store and prepare food.

这种酸对玻璃容器，不锈钢，塑料袋或大多数我们用于储藏和准备食物所用的材料都不会产生任何影响。

Aluminum, though, is especially vulnerable to acid.

但铝却非常容易受到酸的侵蚀。

Here's why.

这就是原因。

Most metals form a protective layer on their surface called an oxide⁴ layer.

大多数金属会在表面生成一种叫做氧化层的保护膜。

Aluminum forms an oxide layer too, but it is very thin, allowing the tomato's acid to easily break through.

铝金属也会形成氧化层，但是这层膜很薄，番茄中的酸能轻易腐蚀透。

This lets the tomato sauce dissolve the aluminum, and it creates grey or black chemicals on top of the lasagna that taste very bad.

由此番茄酱就会溶解铝，在千层面上产生一种灰色或黑色的化学物质，会使千层面变得非常难吃。

The same thing can happen if you use aluminum cookware for acidic sauces.

如果用铝制厨具来做酸味儿酱料，也会发生相同的情况。

Sauce made in an aluminum pot will be grayer and not as tasty as sauce made in other cookware.

铝制锅所做的酱料颜色看起来会更灰些，吃起来也不如其他厨具所做的酱料味道好。

1 leftovers   

n.剩余物，残留物，剩菜

参考例句：

• He can do miracles with a few kitchen leftovers.他能用厨房里几样剩饭做出一顿美餐。
• She made supper from leftovers she had thrown together.她用吃剩的食物拼凑成一顿晚饭。

2 aluminum   

n.(aluminium)铝

参考例句：

• The aluminum sheets cannot be too much thicker than 0.04 inches.铝板厚度不能超过0.04英寸。
• During the launch phase,it would ride in a protective aluminum shell.在发射阶段，它盛在一只保护的铝壳里。

3 stainless   

adj.无瑕疵的，不锈的

参考例句：

• I have a set of stainless knives and forks.我有一套不锈钢刀叉。
• Before the recent political scandal,her reputation had been stainless.在最近的政治丑闻之前，她的名声是无懈可击的。

4 oxide   

n.氧化物

参考例句：

• Oxide is usually seen in our daily life.在我们的日常生活中氧化物很常见。
• How can you get rid of this oxide coating?你们该怎样除去这些氧化皮？