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=====精彩回顧===
Do Carrots Help You See Better
胡蘿卜真的能改善視力嗎？
You heard it over and over again from your mom.“Eat your carrots, they’ll help you see better!”
你總是聽到媽媽說，“把胡蘿卜吃掉，對(duì)你的視力有幫助。”
Well get ready to throw it back in mom’s face,with science!
做好準(zhǔn)備，用科學(xué)知識(shí)反駁她。
Actually before we get to the science,let’s have a history lesson.
實(shí)際上，在開始講解化學(xué)知識(shí)之前，我們先了解一下歷史。
During world war two, British pilots had this fancy new top-secret system for spotting enemy planes called “radar”.
第二次世界大戰(zhàn)期間，英國飛行員有一個(gè)神秘的高級(jí)機(jī)密系統(tǒng)，叫做“雷達(dá)”，可以觀察到敵機(jī)。
No not that radar. Look it up, kids.
不，不是你所知道的那種雷達(dá)。仔細(xì)聽著，孩子們。
Our chemist friend Chad Jones picks up the story from here: “This fancy new radar system gave pilots a huge advantage over their enemy.To keep this advantage a secret the British royal air force started a rumor that their pilots ate lots of carrots to help them see the enemy better at night.”
我們的化學(xué)家朋友Chad Jones為我們帶來了這個(gè)故事：“這種新的雷達(dá)系統(tǒng)讓飛行員們相對(duì)敵人有了更大的優(yōu)勢。為了讓這種優(yōu)勢保密，英國皇家空軍開始傳達(dá)一個(gè)謠言，他們的飛行員吃很多胡蘿卜，幫助他們?cè)谝雇砀宄乜吹綌橙?span style="display:none">DXunMb!JhDD.*。”
Of course it wasn’t the carrots, it was just the radar, but the rumor actually stuck,and it still circulates to this day.
當(dāng)然不是胡蘿卜，實(shí)際上是雷達(dá)發(fā)揮作用。但是謠言確實(shí)發(fā)揮了作用，直到今天仍在流傳。
And the funny thing is, there’s actually a bit of truth to it.
有趣的是，其中確實(shí)不乏真實(shí)的成分。
Carrots have in them a chemical compound called beta carotene (and…no, it’s not named after carrots).
胡蘿卜中含有一種名叫β-胡蘿卜素的化合物（不，這并不是以胡蘿卜命名的）。
When you eat foods with beta carotene,your body converts it into vitamin A.
當(dāng)你食用了含有β-胡蘿卜素的食物時(shí)，你的身體將它轉(zhuǎn)化為維他命A。
And that vitamin A gets turned into retinol.
維他命A隨后轉(zhuǎn)化為視黃醇。
Now retinal is found in your eyes inside vision cells called "rods".
現(xiàn)在，你的眼睛視覺細(xì)胞中可以發(fā)現(xiàn)視黃醇，這些視覺細(xì)胞叫做“視桿細(xì)胞”。
At the very tip of the cell you'll find retinal wrapped inside of a protein.
在這些細(xì)胞的頂端，你可以發(fā)現(xiàn)包裹在蛋白質(zhì)中的視黃醇。
That protein is twisted and compact a little bit like this ball of yarn...
這種蛋白質(zhì)是彎曲的，有點(diǎn)像一團(tuán)紗線。
And retinal sits comfortably inside - like a baby wrapped in a tight blanket. But, when light shines on this happy, sleeping baby...It stretches out from this form (called cis) to this form (called trans).
視黃醇就舒服地包裹在這團(tuán)紗線中——就像嬰兒包裹在一張輕柔的毯子里。但是，當(dāng)陽光照射在這個(gè)快樂熟睡的嬰兒身上時(shí)，它就會(huì)從順式伸展為反式。
This stretching unravels the protein,starting a chain reaction that leads down the rod cell, through the nerves,and to the brain letting you know it's not dark any more.
這個(gè)拉伸過程會(huì)拆解蛋白質(zhì)，開始連鎖反應(yīng)，延伸至視桿細(xì)胞，至神經(jīng)，到達(dá)大腦，讓你知道現(xiàn)在已經(jīng)不再黑暗了。
And that’s how you see light.So where does that leave our carrot myth?
這樣你就看到了光。那么，為什么會(huì)有關(guān)于胡蘿卜的謬論呢？
Well, any food that has vitamin A will be good for your overall eye health.
任何含有維他命A的食物都有益你的雙眼健康。
That’s carrots, lettuce, spinach, mangoes,milk, cheese, cantaloupe and peas.
比如胡蘿卜，生菜，菠菜，芒果，牛奶，奶酪，哈密瓜和豌豆。
But if you already have a diet of vitamin A,these foods won’t actually improve your vision.
但是如果你已經(jīng)食用含有維他命A的飲食，這些食物不會(huì)改善你的視力。
So don’t forget your vitamin A,but don’t count on getting rid of your glasses any time soon just because you’re chomping on a carrot.
所以，不要忘了攝入維他命A，但是不要以為你吃了很多胡蘿卜就可以很快摘下眼鏡。
