【英语时差8,16】热到底是什么？-上

At one time it was believed that heat was a liquid. Sure, that sounds kind of crazy, but if you think for a second, you might see why. Suppose you have an object that’s very hot — say a metal spoon that’s been sitting in hot coffee. Pick it up and you can feel the heat spreading to your hand. The longer you hold on, the more heat seems to enter your hand. Ouch!Well, maybe heat is an invisible liquid that pours from the spoon into your hand. After all, that theory fits all the evidence, doesn’t it?But there’s a problem. Another simple experiment you can do shows heat can’t be a liquid.Take two nails and scrape them together vigorously¹. Now touch the place you were scraping. It’s hot! Let them cool and try it again. It’s hot again!

1 vigorously   

ad.用力地；有力地；剧烈地

参考例句：

• He rubbed his limbs vigorously to get the blood circulating. 他用力摩擦四肢让血液循环开来。
• He shook the blankets vigorously to get rid of the dust. 他使劲抖动毯子以抖掉尘土。