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Sometimes Adding Water Makes Mix Thicker

Usually, we trust common sense to solve problems. Is a runny mixture too thick? Add some fluid. That’ll make it runnier. Except when the fluid makes it thicker. Scientists now think they know why.
靠常識解決問題，這是常理。流質(zhì)混合物太黏稠么？那就加點(diǎn)水，這樣就可以稀薄一點(diǎn)。不過有的時(shí)候會(huì)適得其反?？茖W(xué)家們貌似已經(jīng)發(fā)現(xiàn)了個(gè)中奧秘。

The flow of a runny mixture, technically a suspension, is generally controlled by the size, shape and amount of the solid particles. The researchers started out with tiny hydrophilic glass beads in an organic solvent. Then they added just one percent weight of water. And like when you add water to sand and it clumps together, the mix turned into almost a gel. Microscopic analysis showed that a few beads stick tightly to each water drop.
流質(zhì)混合物流動(dòng)比較緩慢，且有一定限制，這是由其大小、形狀以及固體微粒的數(shù)量決定的。科學(xué)家們 首先對有機(jī)溶劑中的微型親水性玻璃珠進(jìn)行了實(shí)驗(yàn)，先加入溶劑重量1%的水，這時(shí)候有機(jī)溶劑近似膠化，就像往沙子里灌水，微粒都凝結(jié)起來了。通過顯微鏡分 析，科學(xué)家們發(fā)現(xiàn)有一部分玻璃珠和水滴緊密結(jié)合在了一起。

Then the scientists made the glass beads hydrophobic. But the addition of water still made the mixture firmer. Turns out that in this case the beads form loose rings around the water droplets, as this formation minimizes each beads contact with water. The research was published in the journal Science. [Erin Koos and Norbert Willenbacher, "Capillary Forces in Suspension Rheology"—link to come]
科學(xué)家們繼而用憎水性玻璃珠來做實(shí)驗(yàn)。但是，加了水之后，有機(jī)溶劑仍然更黏稠。這就表明這項(xiàng)實(shí)驗(yàn)中，玻璃珠在水滴周圍形成了松圈，因此玻璃珠與水的接觸也就少之又少了。這項(xiàng)研究結(jié)果刊登在《科學(xué)》雜志上。

The scientists say this effect could be used to keep solids from separating out of liquids, or to fine-tune the viscosity of a liquid in engineering. Because sometimes, to make a mixture thicker, just add water.
科學(xué)家們表示這項(xiàng)發(fā)現(xiàn)可用于防止固體物析水，也可用于調(diào)節(jié)工程用液體的黏度。因?yàn)椤狱c(diǎn)水，就可以更黏稠~

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