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You might have noticed how cats delicately lap up milk,
你们可能有注意过猫是用舌头卷起牛奶来喝
while dogs will head over to a water dish and sloppily splash all over your floor.
而狗会 把头伸到碗上方把水溅得满地板都是
Turns out, there's some interesting physics to back up the phrase, "cats rule and dogs drool."
事实上 “猫和狗的口水规则” 是有一些有趣的物理理论 支持的
That's because these pets have to use their tongues to get liquids into their mouths,
这是因为猫狗会用舌头来抵抗重力的影响
fighting against the effects of gravity. And, according to a couple research studies,
从而喝到水 根据一些实验研究
cats and dogs have slightly different techniques that do or don't make a splash.
我们知道了为什么狗会把水溅出来 而猫不会
You and I can sip our milkshakes and soups thanks to suction.
因为我们会用嘴“吸” 所以我们可以抿一口牛奶或者汤
And animals like horses, pigs, and sheep can suck up their water, too.
而像马 猪和羊这类动物也可以把水“吸”到嘴里
And that's because we all have complete cheeks, which means we have muscles and tissues
这是因为我们拥有完整的面颊 意味着我们有肌肉和组织
that let us seal our mouths and create a partial vacuum.
来让我们的嘴巴形成一个可以产生吸力的封闭环境
Basically, you can make a pocket of lower air pressure in your mouth,
主要是你可以在嘴里形成一个比外界气压要低的环境
so the water you're trying to drink gets pushed up by the higher-pressure outside air.
然后外界的高气压就会把水“压”进你的嘴里
And that's suction. But cats and dogs don't have cheeks like ours.
这就是我们所说的“吸力” 但是猫和狗没有像我们这样的面颊
Like lots of predatory mammals, they have incomplete cheeks,
像很多肉食性哺乳动物一样 他们的下巴为了能在捕猎时扩张到最大
which lets them extend their jaws wider to chomp down on their prey.
他们没有完整的面颊
But they /can't/ create that partial vacuum and suck up liquid.
所以它们不能像我们在嘴里形成封闭的低压环境来喝水
Instead, they use their powerful tongues to create columns of liquids like water or milk, and lap it up.
相反 它们会用它们灵活有力的舌头把水或者牛奶 拍卷上来
Using slow-motion video, different groups of researchers have tried to figure out
在慢速摄影下 不同的科学家小组试图搞懂
the physics behind the tongue movements of cats and dogs.
猫和狗舌头动作的物理原理
One study found that cats lower the tips of their tongues to just barely touch the surface of the water.
一个小组发现 猫只会把舌头轻轻地在水的表面 沾一下
Then, they quickly retract their tongues at speeds of almost 80 centimeters per second.
然后 马上以每秒80厘米的速度缩回舌头
The water molecules stick to the cat's tongue thanks to adhesive forces,
多亏了水分子之间互相的凝聚力 水就会沾在猫的舌头上
and stick to each other because of cohesive forces.
被带到嘴里
And this creates a column of water for a split-second, fighting against the force of gravity.
水在这一瞬间形成了一个圆柱 从而战胜了地球的引力
Then the cat slows down its tongue, closes its mouth to trap some of the water. Swallow and repeat.
然后在舌头减速回到嘴里后 猫会把嘴闭上不让水流出来 猫吞下水之后继续重复以上动作
Dogs, on the other hand, are a little more gung-ho than cats, according to a separate study.
在另一方面 根据一项研究 狗在喝水上比猫要更 “同心协力”
These researchers found that dogs splash their tongues deeper into water bowls,
这项研究表明狗把舌头伸进碗里把水溅起像长条状之后
curl them into more of a ladle-shape, and then can retract them at speeds of 700 centimeters per second or more.
会快速地以每秒700厘米甚至更快的速度缩回 舌头
This means more of a dog's tongue is touching the water, so dogs end up making a bigger,
这意味着狗的舌头是直接搅动了整碗水 所以在狗真正喝到水之前
messier water column before they clamp their mouths shut.
他们总会把喝水碗附近弄得一团糟
The larger the dog, the larger the tongue, and the larger the splash.
狗狗越大只 舌头也越大 意味着喝水碗附近也更乱
So next time your dog makes a mess at the water bowl … you can blame physics.
所以下次你的狗把喝水碗附近弄得一团糟的时候 你可以把锅推给物理学
Thanks for asking, and thanks especially to all our patrons on Patreon who keep these answers coming.
感谢你们的提问 更加感谢那些在Patreon上一直为我们作出解答的 热心人
If you'd like to submit questions to be answered, or get some videos a few days early, go to patreon.com/scishow.
如果你想提出问题要我们解答 或者想要比其他人更早地看到我们的视频 请前往patreom.com/scishow
And don't forget to go to youtube.com/scishow and subscribe!
还有别忘了在youtube.com/scishowd上点订阅哦
