TED演讲:为何番茄酱很难倒出来(2)

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　　Now, let's say you apply a weak force very quickly. 现在，假如你突然用很小的力挤番茄酱。

　　The particles bump into each other, but can't get out of each other's way, so the ketchup doesn't flow. 这些小颗粒就会冲到一起，谁都不让谁，当然就不会流动啦。

　　Now, let's say you apply a strong force very quickly. 那如果你突然用很大力去挤番茄酱呢？

　　That extra force is enough to squish the tomato particles, so maybe instead of little spheres, 力度大到可以把颗粒压扁，它们不再是球型，

　　they get smushed into little ellipses³, and boom! 而是变成了椭圆体然后挤爆！

　　Now you have enough space for one group of particles to get passed others and the ketchup flows. 现在有空间让一部分小颗粒穿过去，番茄酱就开始流动了。

　　Now let's say you apply a very weak force but for a very long time. 再假如你用很小的力挤番茄酱，持续一段时间后。

　　Turns out, we're not exactly sure what happens in this scenario⁴. 但是，嗯，我们也不是很清楚会怎样。

　　One possibility is that the tomato particles near the walls of the container slowly get bumped towards the middle, 有一种可能是，靠近瓶壁的番茄颗粒会慢慢移到瓶子中间去，

　　leaving the soup they were dissolved in, which remember is basically water, near the edges. 剩下溶解的液体，基本上就是水留在边缘。

　　That water serves as a lubricant betwen the glass bottle and the center plug of ketchup, and so the ketchup flows. 于是水就会变成瓶壁和番茄酱之间的润滑剂，番茄酱就出来了。

　　Another possibility is that the particles slowly rearrange themselves into lots of small groups, which then flow past each other. 另一种可能就是小颗粒重新组合形成一个个小团儿，然后再慢慢移动。

　　Scientists who study fluid flows are still actively⁵ researching how ketchup and its merry friends work. 研究流体运动的科学家们还在探索到底番茄酱之类的东西是怎么回事呢。

　　Ketchup basically gets thinner the harder you push, but other substances, 番茄酱是你越用力，它们就会变得越稀，但是其他物体呢，

　　like oobleck or some natural peanut butters, actually get thicker the harder you push. 比如欧波力客或者花生酱，你越用力它们反倒变得越稠。

　　Others can climb up rotating rods, or continue to pour themselves out of a beaker, once you get them started. 有一些能顺着转动的棍棒向上流动的，还有一些，一旦你开始倾倒，它们就能一直不停的倾泻。

　　From a physics perspective, though, ketchup is one of the more complicated mixtures out there. 从物理学的角度来讲，番茄酱是世界上少数几个最复杂的混合物之一。

　　And as if that weren't enough, the balance of ingredients and the presence of natural thickeners like xanthan gum, 如果这还不够的话，它的平衡成分以及在水果饮料和奶昔等天然增稠剂黄原胶中的表现，

　　which is also found in many fruit drinks and milkshakes, can mean that two different ketchups can behave completely differently. 能够证明两种不同的番茄酱会有截然不同的表现。

　　But most will show two telltale properties: sudden thinning at a threshold force, 但是一般会出现两种迹象，在临界强度压力下突然变稀，

　　and more gradual thinning after a small force is applied⁶ for a long time. 或者在持续的轻缓挤压下慢慢变得稀薄。

　　And that means you could get ketchup out of the bottle in two ways: either give it a series of long,slow languid shakes  也就是说你有两种方法可以把番茄酱挤出来，要么就是缓缓的慢慢的摇晃，

　　making sure you don't ever stop applying force, or you could hit the bottle once very, very hard. 注意不要停止用力，或者你可以对着瓶底猛地一击。

　　What the real pros⁷ do is keep the lid on, give the bottle a few short, 一般内行会先不打开瓶盖快速的晃动几下瓶子，

　　sharp shakes to wake up all those tomato particles, 把里面的小番茄颗粒摇醒，

　　and then take the lid off and do a nice controlled pour onto their heavenly fries. 然后拧开瓶盖，就可以将番茄酱自如的挤到美味的薯条上啦。

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