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(单词翻译:双击或拖选)
Flash Points People who work with chemicals make sure they know the flash point of each substance in their labs. A flash point is the temperature at which the fumes1 from a liquid can be ignited with a spark. But people who have never taken a chemistry course need to be concerned with flash points as well. For example, the gasoline you put into your car has a flash point of minus forty-five degrees Fahrenheit2. So, unless you live in a climate where the temperature stays below minus forty-five degrees, the fumes from gasoline can ignite from a nearby spark. And that’s why most gas stations have warning signs posted about not smoking while you fill up your tank. Olive oil has a flash point of 437 degrees Fahrenheit. That means if you could heat olive oil to 437 degrees, it would give off a vapor3 that could ignite if a lit match passed through it. Cod4 liver oil has a flash point of 412 degrees Fahrenheit and formaldehyde has a flash point of 122 degrees. Most flash points are inconsequential to the lay person because they occur at such high temperatures. But some, like kerosene5, with a flash point of 100 degrees Fahrenheit, can be cause for concern on a hot day. If you keep an old-fashioned kerosene lamp on your fireplace mantel, you probably shouldn’t light it on a hot summer day, or you might ignite more than just the wick of the lamp.
1 fumes | |
n.(强烈而刺激的)气味,气体 | |
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2 Fahrenheit | |
n./adj.华氏温度;华氏温度计(的) | |
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3 vapor | |
n.蒸汽,雾气 | |
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4 cod | |
n.鳕鱼;v.愚弄;哄骗 | |
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5 kerosene | |
n.(kerosine)煤油,火油 | |
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