時差N小時:液態(tài)氣的燃點

People who work with chemicals make sure theyknow the flash point of each substance in their labs.A flash point is the temperature at which the fumesfrom a liquid can be ignited with a spark.

與化學藥品打交道的人，總會確保自己知道實驗室中每一種物質(zhì)的燃點。燃點是液態(tài)氣體能被火花點燃的溫度。

But people who have never taken a chemistry courseneed to be concerned with flash points as well. Forexample, the gasoline you put into your car has aflash point of minus forty-five degrees Fahrenheit.

但未曾上過化學課的人同樣需要關(guān)注物質(zhì)的燃點。例如，你加入車里的汽油燃點是華氏零下45度。

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 stationshave warning signs posted about not smoking while you fill up your tank.

所以，除非你生活在溫度維持在華氏零下45度以下的環(huán)境里，汽油逸出的煙霧才不會被附近的明火點燃。這也是為什么大多數(shù)加油站都張貼警告標志，告戒人們不要在給車加油時吸煙。

Olive oil has a flash point of 437 degrees Fahrenheit. That means if you could heat olive oil to437 degrees, it would give off a vapor that could ignite if a lit match passed through it. Codliver oil has a flash point of 412 degrees Fahrenheit and formaldehyde has a flash point of 122degrees.

橄欖油的燃點是華氏437度。這意味著如果你把橄欖油加熱至437度，它散發(fā)出的蒸氣完全可以被一根劃過去的、燃著的火柴點燃。魚肝油的燃點是華氏412度，而甲醛的燃點是122度。

Most flash points are inconsequential to the lay person because they occur at such hightemperatures. But some, like kerosene, with a flash point of 100 degrees Fahrenheit, can because for concern on a hot day. If you keep an old-fashioned kerosene lamp on your fireplacemantel, you probably shouldn’t light it on a hot summer day, or you might ignite more thanjust the wick of the lamp.

大多數(shù)物質(zhì)的燃點對于業(yè)外人士來說不重要，因為它們只在高溫條件下出現(xiàn)。但是，一些像煤油一樣，燃點為華氏100度的物質(zhì)，在炎熱的日子里著實令人擔憂。如果你的壁爐架上有一盞老式煤油燈，你最好不要在炎熱的夏天點燃它，因為你點燃的可能不僅僅是煤油燈的燈芯。