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Q & A: Ecology of Fire

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Most recent answer: 10/22/2007
Q:
My biology teacher resently propsed a question: Why is this important, in terms of ecology- Hydrogen+Oxygen=Water Water extinguishes Fire Fire burns Oxygen and Hydrogen I am completely baffled. Please help as best you can!
- Ashley (age 14)
North High, Wisconsin, US
A:
Ashley -

I think that what your teacher is trying to get at is that in ecology, it's important that things balance each other out. Unfortunately, in order for the system you mentioned to make sense, your teacher left one big thing out.

When your teacher said that Hydrogen+Oxygen=Water, she was being a bit unclear. Sure, water is made up of hydrogen and oxygen atoms. But A balloon filled with Hydrogen+Oxygen is a lot different than a balloon filled with Water. For one thing, at room temperature, the Hydrogen+Oxygen balloon would contain a gas that floats up in the air, and the one with water would contain a liquid that sits on the ground.

But a funny thing can happen with that balloon of hydrogen and oxygen. If you set it on fire, it explodes in a big burst and produces water molecules! (Ok, not enough that you'll feel a splash, but they are there.)

So here's a new way of looking at the cycle your teacher described:

(1) Fire burns Oxygen+Hydrogen, making Water.
(2) Water extinguishes Fire.

So here's what this comes down to - the fact that fire produces water as it burns means that it will not burn on forever. The thing it produces can eventually put it out. It's kind of like a checks-and-balances system in nature. (Note: this doesn't mean that big fires can't happen - simply that they can't burn on forever.)

(If your teacher was thinking of something else, don't blame us. It's hard to read minds! -Mike)

-Tamara

(published on 10/22/2007)

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