Quora精選：孩子打破砂鍋問(wèn)到底，你能招架得住嗎？

Answered by Visakan Veerasamy

Visakan Veerasamy的回復(fù)：

I take inspiration from this chemistry professor:

這位化學(xué)教授的故事讓我很受啟發(fā)：

SARAH: Daddy, were you in the shower?
DAD: Yes, I was in the shower.
SARAH: Why?

薩拉：爸爸，你剛剛在洗澡嗎？
爸爸：是呀，我剛在洗澡。
薩拉：為什么？

DAD: I was dirty. The shower gets me clean.
SARAH: Why?
DAD: Why does the shower get me clean?
SARAH: Yes.

爸爸：我身上很臟。洗澡能讓我變干凈。
薩拉：為什么？
爸爸：你是問(wèn)為什么洗澡能讓我變干凈？
薩拉：嗯。

DAD: Because the water washes the dirt away when I use soap.
SARAH: Why?
DAD: Why do I use soap?
SARAH: Yes.

爸爸：因?yàn)槿绻矣梅试淼脑?，水就能把臟東西沖走。
薩拉：為什么？
爸爸：你是問(wèn)為什么我要用肥皂？
薩拉：嗯。

DAD: Because the soap grabs the dirt and lets the water wash it off.
SARAH: Why?
DAD: Why does the soap grab the dirt?
SARAH: Yes.

爸爸：因?yàn)橄阍砟茏プ∨K東西，然后讓水把它們沖走。
薩拉：為什么？
爸爸：你是問(wèn)為什么肥皂能抓住臟東西？
薩拉：嗯。

DAD: Because soap is a surfactant.
SARAH: Why?
DAD: Why is soap a surfactant?
SARAH: Yes.

爸爸：因?yàn)橄阍硎且环N表面活性劑。
薩拉：為什么？
爸爸：你是問(wèn)為什么肥皂是一種表面活性劑？
薩拉：嗯。

DAD: That is an EXCELLENT question. Soap is a surfactant because it forms water-soluble micelles that trap the otherwise insoluble dirt and oil particles.
SARAH: Why?
DAD: Why does soap form micelles?
SARAH: Yes.

爸爸：這個(gè)問(wèn)題問(wèn)得真棒！肥皂之所以是一種表面活性劑，是因?yàn)樗苄纬梢环N水溶性的膠束，這種膠束可以抓住其他不可溶的污垢和油粒子。
薩拉：為什么？
爸爸：你是問(wèn)為什么肥皂能形成膠束？
薩拉：嗯。

DAD: Soap molecules are long chains with a polar, hydrophilic head and a non-polar, hydrophobic tail. Can you say ‘hydrophilic’?
SARAH: Aidrofawwic
DAD: And can you say ‘hydrophobic’?
SARAH: Aidrofawwic

爸爸：肥皂分子是由一個(gè)極性的親水基和一個(gè)非極性的疏水基構(gòu)成的長(zhǎng)鏈。你會(huì)說(shuō)“親水”這個(gè)詞嗎？
薩拉：輕歲。
爸爸：那你會(huì)說(shuō)“疏水”這個(gè)詞嗎？
薩拉：蘇歲。

DAD: Excellent! The word ‘hydrophobic’ means that it avoids water.
SARAH: Why?
DAD: Why does it mean that?
SARAH: Yes.

爸爸：太棒啦！疏水的意思就是防水。
薩拉：為什么？
爸爸：你是問(wèn)為什么是這個(gè)意思？
薩拉：嗯。

DAD: It’s Greek! ‘Hydro’ means water and ‘phobic’ means ‘fear of’. ‘Phobos’ is fear. So ‘hydrophobic’ means ‘a(chǎn)fraid of water’.
SARAH: Like a monster?
DAD: You mean, like being afraid of a monster?
SARAH: Yes.
DAD: A scary monster, sure. If you were afraid of a monster, a Greek person would say you were gorgophobic.

爸爸：這是希臘語(yǔ)！“Hydro”的意思是水，“phobic”的意思是“害怕的”?！癙hobos”就是害怕。所以“hydrophobic”的意思就是“怕水”。
薩拉：像怪獸那樣?
爸爸：你是說(shuō)，像害怕怪獸那樣？
薩拉：嗯。
爸爸：是啊，是個(gè)可怕的怪獸。如果你害怕怪獸，希臘人就會(huì)說(shuō)你是“疏怪獸的”。

(pause)

（停了一會(huì)兒）

SARAH: (rolls her eyes) I thought we were talking about soap.
DAD: We are talking about soap.

薩拉：（轉(zhuǎn)了轉(zhuǎn)眼珠）我以為我們?cè)谟懻摲试怼?
爸爸：我們是在討論肥皂呀。

(longish pause)

（停了好一會(huì)兒）

SARAH: Why?
DAD: Why do the molecules have a hydrophilic head and a hydrophobic tail?
SARAH: Yes.

薩拉：為什么？
爸爸：你是問(wèn)為什么肥皂分子有一個(gè)親水端和一個(gè)疏水端？
薩拉：嗯。

DAD: Because the C-O bonds in the head are highly polar, and the C-H bonds in the tail are effectively non-polar.
SARAH: Why?

爸爸：因?yàn)槎瞬康奶佳蹑I極性強(qiáng)，尾部的碳?xì)滏I完全非極性。
薩拉：為什么？

DAD: Because while carbon and hydrogen have almost the same electronegativity, oxygen is far more electronegative, thereby polarizing the C-O bonds.
SARAH: Why?

爸爸：因?yàn)樘己蜌潆娯?fù)性幾乎相同，而氧的電負(fù)性更強(qiáng)，所以碳氧鍵有極性。
薩拉：為什么？

DAD: Why is oxygen more electronegative than carbon and hydrogen?
SARAH: Yes.

爸爸：你是問(wèn)為什么氧的電負(fù)性強(qiáng)于碳和氫？
薩拉：嗯。

DAD: That’s complicated. There are different answers to that question, depending on whether you’re talking about the Pauling or Mulliken electronegativity scales. The Pauling scale is based on homo- versus heteronuclear bond strength differences, while the Mulliken scale is based on the atomic properties of electron affinity and ionization energy. But it really all comes down to effective nuclear charge. The valence electrons in an oxygen atom have a lower energy than those of a carbon atom, and electrons shared between them are held more tightly to the oxygen, because electrons in an oxygen atom experience a greater nuclear charge and therefore a stronger attraction to the atomic nucleus! Cool, huh?

爸爸：那就復(fù)雜了。對(duì)于這個(gè)問(wèn)題有多種解釋，取決于你采用的是鮑林標(biāo)度還是密立根標(biāo)度。鮑林標(biāo)度的原理在于，在某一元素作為基準(zhǔn)的條件下，通過(guò)計(jì)算不同元素的分子與其鍵能之差從而計(jì)算出相對(duì)電負(fù)性。而密利肯尺度是基于電子本身親和能和電離能的性質(zhì)。但最終還是歸結(jié)于有效核電荷數(shù)。氧原子的價(jià)電子能較碳原子價(jià)電子能低，兩者之間的共用電子會(huì)被氧緊緊束縛，因?yàn)檠踉觾?nèi)的電子受到了更強(qiáng)的核電荷作用，所以會(huì)被原子核強(qiáng)吸引！酷吧？

(pause)

（停了一會(huì)兒）

SARAH: I don’t get it.
DAD: That’s OK. Neither do most of my students.

薩拉：我沒(méi)聽(tīng)懂。
爸爸：沒(méi)關(guān)系。我的大部分學(xué)生也不懂。

EDIT: Here's the original source: A DIALOGUE WITH SARAH, AGED 3: IN WHICH IT IS SHOWN THAT IF YOUR DAD IS A CHEMISTRY PROFESSOR, ASKING “WHY” CAN BE DANGEROUS

補(bǔ)充：以下是原文鏈接：與三歲的Sarah的對(duì)話：如果你爸爸是化學(xué)教授，追問(wèn)“為什么”后果可能會(huì)很?chē)?yán)重哦

About Stephen McNeil

關(guān)于Stephen McNeil

Stephen McNeil is an Assistant Professor of Chemistry at the University of British Columbia Okanagan in Kelowna, British Columbia. To date, he has been interviewed on the radio four times: twice he was talking about chemistry, and twice he was talking about pirates. His favourite element is the element of surprise.

Stephen McNeil是一名化學(xué)助理教授，就職于不列顛哥倫比亞省基隆拿市的英屬哥倫比亞大學(xué)（University of British Columbia）歐墾那根校區(qū)。迄今為止，他一共接受過(guò)四次電臺(tái)訪問(wèn)：兩次聊的是化學(xué)，另外兩次聊的是海盜。他最喜歡的元素是the element of surprise（注1）。

注1：這句話里的element是雙關(guān)，element有元素的意思，element of surprise 指出其不意，不是指自己被驚喜，而是說(shuō)自己具備出人意料的優(yōu)勢(shì)。