Hi, I'm Jessica

嗨，我是Jessica

Today I'm gonna talk to you about a chemical demonstration I like to call

今天我要講的化學(xué)演示叫作

colorful indicators

多彩指示劑

Indicators show us what we normally wouldn't be able to see

指示劑/物能夠指示出我們一般看不到的情況

from the canary in the coal mine

包括煤礦地中的金絲雀

to a paint that changes color with temperature

隨溫度改變顏色的顏料

to the acid-base indicators we'll be seeing today

以及今天我們要看的酸堿指示劑

And chemist Dr. Bassam Shakhashiri

化學(xué)家Bassam Shakhashiri博士

here he is

這就是他了

is going to be showing us the demo

他將為我們進(jìn)行演示

He's the president of the American Chemical Society

他是美國化學(xué)學(xué)會(huì)主席

and performing this demo right here at MIT

演示是在MIT這里進(jìn)行的

You know, what I'm going to do is an experiment

下面我要做的實(shí)驗(yàn)

using another form of carbon dioxide that's called dry ice

將用到另一種形式的二氧化碳，叫作干冰

Dry ice is solid carbon dioxide

干冰是固態(tài)二氧化碳

and you'll notice I'm putting what on?

看這里我戴上了什么

Putting gloves

帶上手套

And I'm going to open this bucket and pick up 3 chunks of carbon dioxide

我將打開這個(gè)桶，并取出三塊二氧化碳

Solid, this a solid carbon dioxide

這是固態(tài)二氧化碳

Its temperature is -78 degrees Celsius

其溫度是-78攝氏度

It's very cold

非常冰冷

Dry ice changes from being solid to a gas by a process we call...

干冰從固態(tài)變?yōu)闅鈶B(tài)的過程叫作…

sublimation

升華

Sublimation is happening right now but we can't see it

升華正在發(fā)生，但我們看不到

how come we can't see it?

為什么看不到呢

Because carbon dioxide is gas. It's what?

因?yàn)槎趸际菤怏w，它是怎樣的