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
他將為我們進行演示
He's the president of the American Chemical Society
他是美國化學學會主席
and performing this demo right here at MIT
演示是在MIT這里進行的
You know, what I'm going to do is an experiment
下面我要做的實驗
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?
因為二氧化碳是氣體,它是怎樣的