【英语时差8,16】了解暖水瓶的工作原理-下

What’s A Good Insulator¹? How about air? Air is, in fact, a pretty good insulator, which is why styrofoam keeps things hot. It’s full of air. But even better than that would be a vacuum. Because there’s nothing in it to heat up, heat can’t conduct through it. A vacuum is the best insulator of all, and that’s the principle behind a thermos². A thermos is a flask³ with a double-walled container inside it. Air is removed from the space in-between the walls. Now heat can’t escape from the soup; it’s surrounded by a vacuum. And to further help hold in heat the inside walls are silvered to reflect heat rays which try to escape.

1 insulator   

n.隔离者；绝缘体

参考例句：

• Few substances can equal fur as an insulator.作为绝缘体很少有其他材料能与动物皮毛相媲美。
• A loose mulch acts on the surface as an insulator.疏松的覆盖物在土壤表面起了隔热的作用。

2 thermos   

n.保湿瓶，热水瓶

参考例句：

• Can I borrow your thermos?我可以借用你的暖水瓶吗？
• It's handy to have the thermos here.暖瓶放在这儿好拿。

3 flask   

n.瓶，火药筒，砂箱

参考例句：

• There is some deposit in the bottom of the flask.这只烧杯的底部有些沉淀物。
• He took out a metal flask from a canvas bag.他从帆布包里拿出一个金属瓶子。