【英语时差8,16】吸管的工作原理（上）

When you sit down to a glass of iced tea with a straw in it, you might say that you are sucking the tea up through the straw. In fact, a more accurate¹ description would be to say that the atmospheric² pressure is pushing the liquid up the straw. With the straw just sitting in the glass, the pressure on the surface of the tea is the same all over, including on the little bit of surface inside the straw. When you suck the air out of the straw, you decrease the pressure inside the straw, allowing the higher pressure on the rest of the surface to push the tea up the straw and into your mouth. Because it is really the atmosphere that is doing the pushing, the atmospheric pressure limits how high water will go up a straw. At sea level, the air pressure is enough to support a column³ of water about thirty feet high. Even if you could suck all the air out of a forty-foot straw, the water wouldn’t rise more than thirty feet. In space, where there isn’t any atmospheric pressure, a straw wouldn’t work at all.

1 accurate   

adj.正确无误的；准确的，精确的

参考例句：

• He has made an accurate measurement of my garden.他准确地丈量了我的花园。
• He is always accurate in what he says and does.他说的和做的总是正确无误。

2 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

3 column   

n.列，柱形图；专栏；圆柱；纵队

参考例句：

• I often read his column in the local paper.我经常在当地的报纸上看到他的专栏文章。
• A column of soldiers marched down the highway.一个士兵纵队沿着公路行进。