时差N小时 可乐除铁锈（上）

Let's begin with a cleaning tip:

先分享一个去污小妙招：

If you have some tarnished¹ or corroded² brass³ that you want to clean, an old brass candlestick for example,

如果你想要清除铜锈，例如铜烛台，

you can use Coca-Cola, or any other cola soft drink, and that brass will come clean.

可以使用可口可乐或者其它可乐饮料，清洗后的烛台光亮如新。

And if Cola is such an effective cleaner of corroded metal, what is it doing to the inside of your stomach?

如果可乐能有效清洁金属锈斑，那么可乐对人体的胃会产生什么影响呢?

Cleaning with Cola on today's moment of science.

今日科学一刻：用可乐清洗物品

Cola cleans brass because it's mildly acidic.

可乐能清洁铜锈是因为可乐呈弱酸性。

Here's what happens: When brass or another metal alloy⁴ becomes tarnished,

经常遇到这种情况：当黄铜或其他金属生锈时，

this means that there has been a chemical reaction between the oxygen in the air and one of the metals in the alloy.

是因为空气中的氧气和合金中的某种金属发生了化学反应。

Oxygen atoms combine with metal atoms to form what's called an oxide⁵, and this oxide is what makes the metal appear tarnished.

氧原子结合了金属原子，形成所谓的氧化物。氧化物就是金属锈。

1 tarnished   

（通常指金属）（使）失去光泽，（使）变灰暗( tarnish的过去式和过去分词 )； 玷污，败坏

参考例句：

• The mirrors had tarnished with age. 这些镜子因年深日久而照影不清楚。
• His bad behaviour has tarnished the good name of the school. 他行为不轨，败坏了学校的声誉。

2 corroded   

已被腐蚀的

参考例句：

• Rust has corroded the steel rails. 锈侵蚀了钢轨。
• Jealousy corroded his character. 嫉妒损伤了他的人格。

3 brass   

n.黄铜；黄铜器，铜管乐器

参考例句：

• Many of the workers play in the factory's brass band.许多工人都在工厂铜管乐队中演奏。
• Brass is formed by the fusion of copper and zinc.黄铜是通过铜和锌的熔合而成的。

4 alloy   

n.合金，(金属的)成色

参考例句：

• The company produces titanium alloy.该公司生产钛合金。
• Bronze is an alloy of copper and tin.青铜是铜和锡的合金。

5 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？