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Q & A: Why is there so much Nitrogen?

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Q:
Why is there so much of nitrogen in the air? Thanks
- Samuel Yip (age 12)
Singapore
A:
Good question, Samuel.

The air around us is made of several different gases. Mostly nitrogen (78%) and some oxygen (21%) and traces other gases like argon, water, carbon dioxide, ozone, and more.

These gases weren't always in our atmosphere, and they came from all sorts of different places. Scientists believe that most of the nitrogen in the air was carried out from deep inside the earth by volcanoes.

The nitrogen molecule is heavier than most other molecules in the atmosphere, so it tends to settle towards the bottom. Other lighter gases, like hydrogen or helium, would tend to the top of the atmosplere, where it is more likely to be lost to space. So the heavier gases like nitrogen and oxygen tend to stick around, since they are at the bottom of the atmosphere.

I hope this answers your question.


math dan

(republished on 08/01/06)

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