时差N小时 火是如何形成的?(上)（在线收听）

It's one of our most important tools, and holds prominent place in many ancient philosophies and religions.

这是我们最重要的工具之一，并且在很多古代哲学和宗教中地位显著。

The ancient Greeks believed that fire–along with earth, water, and air–was one of the four essential elements that made up the world.

古希腊人认为，火，土，水和气是构成世界的四个基本要素。

We now know that the world's a lot more complicated, with over a hundred elements of matter which can be combined in a tremendous variety of ways.

如今，我们都知道世界的构成更加复杂，由上百种物质组成，同时这些物质又可以以无数种不同的方式结合。

This might leave you wondering where fire fits in. What exactly is fire?

因此，你可能会好奇，火从哪里来，火又是什么呢？

Watching a flame dance through the air, you might conclude that fire's a gas, like oxygen or carbon dioxide.

看到空气中跳动的火苗，你可能会觉得火是一种气体，像是氧气，二氧化碳等气体。

It's not. Fire can burn fuel that's a gas, or a liquid, or even a solid–as in the case of glowing charcoal.

实则不然。火可以使气体，液体甚至是固体燃料燃烧-如燃烧的木炭。

But the fire itself isn't any of these things.

但是火本身不属于上述这些形态。

In fact, fire isn't anything at all.

实际上，火自身没有形态。

It's not its own type of matter; it's something that matter can do.

虽然不是物质，却能够起到一些物质的作用。