Let's say your car breaks down in the middle of the desert, or in a howling blizzard.

來說說如果你的車子在沙漠或暴風雪中拋錨了

Your phone battery is dead,

你的手機沒電

and you didn't stock up on food and water like you maybe should've.

然後你也沒儲存食物和水，假設你或許原本應該有

How are you gonna get out of this one?

你會如何脫離這個險境？

If you find yourself in a survival situation, you're going to have certain priorities:

如果你發現自己還倖存著，你要有個特定的先後順序：

water, not dying of exposure, not being mauled by wild animals, and,

水、小心曝曬、別被野生動物攻擊，和

you know, getting back to wi-fi as soon as possible so you can watch SciShow.

你知道的，盡快回到有無線網路的地方，才能看 SciShow

For most folks, food can actually be a lower priority.

對於大多數的人而言，食物實際上比較不重要

But there's a lot of bad survival info out there.

但是有很多不好的生存守則

Some tips seem too good to be true, and they are.

有些訊息似乎太理想化，也的確是如此

Others are ingrained enough to be common knowledge, except they're wrong.

而有些已經根深柢固地被認為是基本常識，雖然它們是錯的

So here's a list of 8 survival tips you definitely shouldn't follow,

所以你絕對不能照做這 8 項生存守則

and what to do instead.

還有你應該怎麼做

First up: water.

第一：水

What about all the snow that's piling up in the blizzard?

那麼堆積在暴風雪中的雪如何呢？

That is made of water.

那是從水來的

Snow can be safe to eat, especially if it's freshly fallen.

雪是可以吃的，尤其是剛下的雪

While it can collect contaminants as it falls, things like soot from wood fires and coal plants,

就算它降落時會收集到汙染物，像是燒木材和煤的煙塵

that generally won't be enough to hurt you.

一般來說還不至於傷到你

Snow that's already on been the ground for a while is riskier, since it might have accumulated,

而積在地面一段時間的雪會比較有風險，因為它可能已經累積

like, who knows what, pollutants from the road, maybe,

像是，誰知道，來自地面的汙染物，之類的

you know, you can insert your own yellow snow joke here.

你懂的，你可以放你尿過的雪在這

But eating snow might be a bad idea for a different reason:

但基於以下幾點，吃雪可能不是個好主意

It has to melt inside your body, and that uses your body heat.

它必須在你的體內融化，而這樣會耗掉你的體熱

Water has a high heat capacity, because it has

水有很高的比熱，因為它有

pretty strong bonds holding the molecules together.

很強的鍵結能把分子聚在一起

So you need a lot of energy to break those bonds to boil liquid water or melt ice.

所以為了讓冰溶化或讓水蒸發，你需要很大的能量去破壞那些鍵

Energy your body would otherwise be using to keep you warm.

體內的能量也會用來維持你的體溫

Plus, you'd have to eat a lot of snow to get enough water, since

所以你更要吃很多的雪來補充水分，因為

piles of snow contain a lot of air.

雪裡面有許多的空氣

So to keep your body temperature from falling too much, find a way to melt the snow first.

所以為了不要讓你的身體失溫，先設法去融雪

But the worst way to do that is to like hold it against your skin to melt it.

但融雪最糟的方法就是用你的皮膚包覆著它

Don't do that, it's still going to cool you down.

別那麼做，這樣你還是會失溫

If you're in the desert, don't count on cactuses as like secret jugs of fresh spring water.

如果你在沙漠中，別指望仙人掌會有秘密水壺般的新鮮泉水

There's a lot of water in there, yeah.

那裡是有很多的水

But there's also a bunch of noxious chemicals.

但同時也有許多有害的化學物質

Cactuses use an unusual type of photosynthesis, called CAM.

仙人掌用一種特殊的光合作用，叫作 CAM

CAM photosynthesis uses way less water than other kinds, so it's handy in the desert.

CAM 需要的水比其它種的光合作用還要少，所以它才能自由地在沙漠中

CAM plants gather CO2 through pores at night and store it in the form of organic acids.

用 CAM 的植物，晚上透過氣收集二氧化碳並用有機酸的形式儲存

Then they can close those pores during the day to minimize water loss,

之後它們便可在白天關上氣孔，讓水分的流失降到最少

using the stored carbon to get on with the light-dependent parts of photosynthesis.

在光合作用的光反應時，用儲存起來的二氧化碳生活

For storage, they mainly use malic acid, which isn't so bad for you.

為了儲存，它們主要用蘋果酸，這不會很傷你的身體

It's in various fruits, although too much can irritate your mouth.

它在很多水果中都有，雖然吃太多會讓你的嘴巴不舒服

But many CAM plants also make oxalic acid.

但許多 CAM 植物也會製造草酸

Oxalic acid is toxic, because it binds to calcium, which can mess up your body.

草酸是有毒的，因為它會和鈣結合，而你的身體會失調

It can also build up in your kidneys in the form of calcium oxalate,

它也會變成草酸鈣，堆積在你的腎中，

the stuff kidney stones are made of.

所謂的腎結石就是這麼來的

In addition to the acids, a lot of cactus flesh contains alkaloids, which are a diverse

除了這些酸類，許多仙人掌的肉有植物鹼基，那是個

family of plant chemicals that generally aren't nice to eat and can really affect your body.

植物界中化學物質的大家庭，通常不太適合拿來吃，而且對人體有一定的影響

Cactus juice won't get you high, like it did to Sokka in Avatar: The Last Airbender.

仙人掌汁不會像「降世神通：最后的氣宗」(美國動畫) 一樣讓你變嗨

But it can make you sick enough to cause puking or diarrhea,

它反而會讓你生病，引發嘔吐或痢疾

which will dehydrate you and make matters worse.

這將讓你脫水，情況會變更糟

Fishhook barrel cactuses and young prickly pear cactuses contain few enough of the unpleasant

魚鉤狀的圓筒仙人掌和年輕的梨果仙人掌包含一些不好的

chemicals to be kind of edible when raw.

化學物質，讓它在還沒成熟的時候變成能吃的東西

They still don't taste good, but they'll do in a bind.

他們仍不好吃，但他們將能在如此窘境發揮作用

But you'd better be pretty confident in your botany skills.

但你最好對自己的植物學技能有自信

Bodily fluids are also mostly water, so you might think you can recycle them.

水也是體內最多的液體，所以你應該要想想能不能回收那些東西

Drinking urine might help you survive ever so slightly longer,

喝尿或許可以讓你撐久一些

but it's only safe to do for a day or so.

但這不是長久之計

That's because the waste products in your pee are waste for a reason.

尿中的廢物之所以被排掉，有它的原因

If you put them back in your body, they'll build up faster than your kidneys can eliminate them.

如果你再把它放回體內，它們會累積得比腎臟排出還快

And that can send you into a state similar to kidney failure, with your body unable to

然後會讓你進入腎功能衰竭的狀態，你的身體沒辦法

process all of the potassium, nitrogen compounds, and calcium you're throwing at it.

處理所有的鉀、氮化合物，和你丟向它的鈣

As for blood… it's sometimes safe to eat in small amounts.

至於血... 有時候少量攝取是安全的

In certain places, it's fairly common, but that's more for its

在特殊的時候，這是很正常的，但血中的

protein and iron content than as a source for water.

蛋白質和鐵比水還多

In large amounts, which you'd need to stay hydrated, blood contains more iron than your

在你需要保持水分的情況下，喝太多血會讓血液裡的鐵含量超過

body can handle, and it becomes toxic.

身體的負荷，然後就會中毒

Your body tries to store it in places like your heart and liver,

你的身體試著把它收進心臟或肝臟之類的地方

but that can lead to organ failure and death.

但這麼做會導致器官衰竭而死

Plus, you're at risk from bloodborne pathogens.

加上，你正處於血源性病原體的危機

So going full vampire to survive is probably not the best idea.

所以為了活下去而當吸血鬼八成不會是個最棒的主意

But let's say you've found some water, and now you need a way to get home without GPS.

不過讓我們假設你找到一些水，現在需要一個沒有導航也能回家的方法

And maybe you've heard that moss always grows on the north sides of trees.

或許你有聽過，苔癬總是從樹木的北方開始生長

This is one of those things that's true in general, but not 100% reliable all of the time.

普遍來說，這是其中一項正確的事，但並不是每個時候都完全可靠

So it's not so useful for navigation.

所以對導航來說，這不實用

Here in the northern hemisphere, the northern side of a tree will get the least sunlight,

在北半球，樹木的北邊照到的陽光最少

thanks to the Earth's tilt.

多虧地球的傾斜

That means the northern side of the tree is most likely to be shady, cool, and damp,

這代表樹木的北邊通常都是陰冷潮濕

all things that moss likes.

和各種苔癬喜歡的環境

Mosses are non-vascular plants, which aren't as good at retaining water as other types of plants.

苔蘚是非維管植物，保留水分的能力沒有其它種類的植物來的好

They essentially lack the plumbing to transport water inside of them,

它們基本上就是缺少輸送水分的管子

so they need all the moisture they can get.

所以它們需要所有能夠取得的水分

So if some other situation is creating good conditions on any particular side of a tree,

所以在樹木的任何一側，如果有其它情況讓狀態變好

moss can grow there just fine.

苔癬還是能在那生長

It's not necessarily pointing north, it's just the nice-for-moss side.

它不一定就是指向北方，只是通常會適合苔癬生長

You're going to need some shelter too, or at least a way to stay warm.

你也需要一些陰涼處，或是一個至少能保暖的地方

And you might have seen people in old-timey books or shows

而你可能看過很久以前的書本或節目

giving a swig of booze to warm someone up, especially in a blizzard.

為了暖活身子，會大口地喝酒，尤其是在暴風雪中

This one almost seems intuitive, because alcohol brings a flush of warmth to your cheeks.

這點看起來幾乎是很直觀的，因為酒精會讓你的臉頰紅紅熱熱的

But that is the exact opposite of what you want if you need to stay warm.

但如果你要保暖，這麼做的結果和你想要的完全相反

Alcohol is a vasodilator, meaning it opens up the blood vessels near the surface of your skin,

酒精是血管擴張劑，也就是說它會擴張皮膚表面的血管

probably by altering your brain's blood vessel controls.

大概是因為大腦的血管控制改變了

That increased blood flow is why you might feel or look flushed when you're drunk.

就是因為血流量的增加，喝酒時臉頰感覺或看起來可能會紅紅的

But it also transports warmth towards the surface of your skin,

但它也會傳送熱能到皮膚表層

where it can conveniently diffuse away from your body and into the colder air nearby.

那些能輕易從體內散播出去到附近空氣比較冷的地方

Thanks, thermodynamics.

謝囉！熱力學

When your body is trying to stay warm, it actually constricts those blood vessels to

當你的身體試著要保持溫暖，實際上它要壓縮那些血管來

try and conserve warmth in your internal organs and your brain,

試著保存體內器官和大腦的溫度

which need to stay at 37 degrees Celcius to keep ticking.

而他們需要保持攝氏 37 度來持續運轉

Don't undo that hard work.

別放著那項困難的工作不管

And if you're cold, rubbing yourself to stay warm seems intuitive,

如果你覺得冷，搓熱自己來保暖這件事看起來很直觀

the friction generates a bit of warmth.

磨擦會生熱

But once frostbite sets in, that is a horrible idea.

但當有凍瘡的時候，那會是很可怕的想法

On a cellular scale, frostbite means ice crystals are starting to form in your tissues.

對細胞來說，凍瘡意味著冰晶開始在你的組織中形成

And ice crystals are sharp.

而冰晶很鋒利

They can puncture cell membranes and other cellular structures,

他們可以刺穿細胞膜和其它細胞中的組織

not to mention freeze the water those cells were using to live.

更別提凍結那些細胞賴以維生的水分

Rubbing will jostle those sharp chunks of ice around,

磨擦會擠到那些一塊一塊鋒利的冰

and cause them to rupture nearby cells.

導致它們周遭的細胞破裂

That's going to make things much worse.

那會讓事情更糟

Also, even though it's painful, it's not good to thaw those frostbitten toes if they're

而且，即使它很痛，也盡量不要把生凍瘡的腳趾解凍，如果它們

still at risk of refreezing.

仍有機會再次被凍住的話

More ice forming again will do more damage and risk more permanent loss of tissue.

有更多的冰再次形成後造成更大的傷害，讓組織永久壞死的風險也更高

Frostbite mostly affects the extremities.

凍瘡主要都在四肢

If hypothermia actually sets in, meaning the body's core temperature has dropped below

如果真的開始失溫了，就代表著身體核心的溫度已經降到

35 degrees, the key is careful, slow reintroduction of warmth.

35 度以下，重點就是要小心的，慢慢的再次暖起來

Plunging a victim of hypothermia in a hot tub could cause irregular heart rhythm

將失溫的患者浸入熱水中，會導致心律不整

or even a heart attack.

甚至心臟病發作

The proper way to treat frostbite and hypothermia is, like, by a doctor,

處理凍瘡和失溫適當的方法就是，像是看醫生

but when that's not possible, caution is best.

但當這部可行時，越慎重越好

Try to sit tight, and don't risk doing more harm.

試著坐穩，別再冒更多險

Finally, on your way home, it's best if you can avoid being mauled,

最後，在你回家的路上，如果可以的話，最好避免被任何東西打傷、

bitten, or stung by anything.

咬傷，或刺傷

But if you are, be careful what advice you listen to.

但是如果不幸發生了，要留意那些你聽過的建議

Like, that one myth that tells you to like, slice open the snakebite and suck out the toxin.

比如說，一個錯誤的觀念，像是切開被蛇咬的傷口，吸出毒液

The effects of snakebite vary based on the kind of snake and the venom it's packing.

被不同種類和毒性的蛇咬傷後會有不同的影響

Some bites may cause severe tissue damage and internal bleeding,

有些會導致組織壞死和內出血

while others are neurotoxins, there's a bunch!

有些則是神經毒素。還有一大堆！

Snake venoms are fascinating!

蛇的毒素很有趣！

So in reality, this so-called “treatment” will increase the risk of the wound getting infected,

所以事實上，這所謂的「治療」會增加傷口感染的風險

possibly spread the venom into the victim's bloodstream much faster,

很有可能會將蛇的毒素價速散步到患者的血液中

and not actually remove very much venom.

而且並不會去除太多的毒素

In other words, don't do it.

簡單來說就是，別這麼做

An article published in the New England Journal of Medicine in 2002

在 2002 年，新英格蘭醫學雜誌中曾發表的某篇文章

strongly discourages incision and suction for snakebites.

強烈地反對切開並吸出被蛇咬的傷口這件事

Instead, they recommend keeping the wound below the level of the heart,

反而建議將傷口保持在心臟以下的高度

keeping the victim warm, avoiding tourniquets or any kind of restrictive clothing or jewelry,

讓傷者保持溫暖，避免止血帶或其它任何緊繃的衣服或首飾

and getting to the hospital as soon as possible.

並盡快就醫

Hospitals can administer antivenom to neutralize the bite.

醫院可以給予抗蛇毒血清以中和傷口

Antivenom is made up of antibodies that are carefully made to bind to the venom

抗蛇毒血清是由精心製成的抗體和毒素結合而成

and stop it from having effects on your body.

用它來停止毒液對你身體造成的影響

Since different snakes make different kinds of venom, one of the main things

由於不同的蛇產生的毒素種類不同，其中一個重點

is to remember as much as you can about what the snake looked like.

就是盡你所能地記住蛇的長相

You don't need to, like, catch the snake and, like, bring it along with you though,

你不需要像是抓住蛇、帶著牠，之類的

that's not gonna help; nobody's gonna like that.

那沒什麼幫助，沒人喜歡這麼做

And some kinds of antivenom work for multiple kinds of snakes.

而有些種類的抗蛇毒血清適用於多種蛇類

It depends on the exact cocktail of antibodies.

它取決於抗體確切的混合物

So you're best off leaving the treatment, hey, to professionals,

所以，嘿！你最好把治療留給專業人士

because I don't think you have a venom-binding antibody serum in your back pocket,

因為我不認為你的後背包裡有混合毒液的抗體血清

and if you do, that should be refrigerated!

就算你有，那也應該要放冷藏！

And last but not least, suppose you're stranded on the shore instead of in a forest

最後但也很重要的一點，假設你不在森林裡，而是被困在岸邊

and got a nasty jellyfish sting.

被可惡的水母刺傷

Should you just… pee on it?

你應該... 尿在上面嗎？

Besides sounding totally gross and weird, it's not worth it.

除了聽起來相當噁心又詭異之外，它不值得你這麼做

Pee doesn't work, and it might even make things worse.

小便起不了作用，而且可能還會搞砸一切

Jellyfish tentacles contain stinging cells called cnidocytes,

水母的觸手含有刺刺的細胞，叫作刺絲胞

which discharge tiny harpoon-like stingers when they touch you, plus the venom.

當他們碰到你時，它會發射像魚叉一樣的小刺，外加毒素

And some of that venom can poke holes in cells or cause all kinds of biological mayhem.

某些毒素能刺穿細胞或者造成生物的混亂

But not many of the cnidocytes on a stinging tentacle fire when you first touch it.

但當你第一次碰它的時候，並不是很多觸手上的刺絲胞都會開火反擊

So the trick is to get it off you without triggering the thousands of others.

所以訣竅就是在沒有觸發其它上千個觸手前離開它

The myth claims that urine will neutralize those cnidocytes,

有個迷思說到，尿液可以中和那些刺絲胞

so they don't go off and sting you.

所以他們不會發射刺你

But certain chemical changes can fire off cnidocytes as well as touch.

但特定的化學變化會觸發刺絲胞，就像碰到它們一樣

Like, alcohol is known to trigger them.

比如說，酒精就是一個已知會觸發它們的例子

And at least one study has shown that urine can do so as well.

而且至少有一篇研究顯示尿液也有這個效果

A 2017 study published in the journal Toxins found that many popular sting treatments,

一篇 2017 年刊於雜誌〈毒物〉(一本毒理學學術刊物) 的研究點出，許多常見的刺傷治療

including scraping the stung area with a credit card or shaving cream, don't work.

包括用信用卡或刮鬍泡刮被螫到的區塊，都沒效

Seawater can help you rinse them off, but it won't chemically prevent them from firing.

海水可以幫你清洗掉，但在化學上沒辦法避免被螫

That's where jellyfish live, after all.

要知道，水母就是住在那

Instead, they found that a good dousing with vinegar is best,

反之，它們發現醋酸是減輕疼痛最好的方法

which is just the chemical acetic acid.

它就只是化學上的乙酸

That will actually neutralize the ones that haven't stung you yet,

在你還沒被螫前，它可以真正發揮中和的效果

maybe by bringing the pH too low for them to function.

或許是因為對他們而言酸鹼值太低以致無法進行攻擊

Then the tentacles can be carefully plucked away by tweezers,

然後就可以小心地用鑷子扯掉觸手

and heating pads will help ease the pain of a sting.

加熱墊能幫助減輕刺痛

Now, you may never need to use any of these tips, I certainly hope you don't,

現在，你或許不會需要用到其中任何一個訣竅，我一定是希望你用不到

but there's a lot of misinformation out there, and emergency survival is something

但是外界有許多錯誤的消息，而急救是

you don't really want to take chances with.

你最不想嘗試的事情

So a little bit of scientific rigor is maybe the best way to know if a tip could save your life

所以最好了解一點科學的嚴謹性，如果它關乎到救你一命

or make things much worse.

或者搞砸一切

Thanks for watching this episode of SciShow!

這集 SciShow，感謝你的收看！

If you want to keep learning more about the weirdness of human bodies

如果你想了解更多關於人體的奧秘

and the world we live in, you can go to youtube.com/scishow to subscribe.

和你居住的世界，你可以上 youtube.com/scishow 並訂閱

[♪ OUTRO]

[尾奏]