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What are the Components of Air?

When humans breathe, they draw oxygen from the air and release carbon dioxide back into it.
The burning of fossil fuels can alter the components of air.
Nitrogen is the most abundant element in Earth's air.
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  • Written By: Michael Anissimov
  • Edited By: Bronwyn Harris
  • Last Modified Date: 22 September 2014
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There are five major components of air: nitrogen (78.0842%), oxygen (20.9463%), water vapor (about 1%), argon (0.93422%), and carbon dioxide (0.03811%). Trace components make up another 0.002%. Out of all these substances, the one that animals (including humans) need to survive is oxygen, while plants require carbon dioxide and nitrogen.

The respiration of animals consumes oxygen and produces carbon dioxide as a byproduct, while plants consume carbon dioxide and produce oxygen. The world's ecosystems depend on this balance. The components of air may be altered by human activity, such as the burning of fossil fuels, which has increased the proportion of carbon dioxide in the atmosphere.

Air has been a subject of study for scientists for hundreds of years. Like other gases, air behaves according to Boyle's Law, which states that the pressure and volume of a gas are inversely proportional in a closed system where the total quantity of gas and its temperature remain fixed. This means that a person can decrease the volume of air by compressing it, but its pressure will increase proportionally.

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It is possible to pump air into an elastic membrane, like a balloon, to inflate it. Because the pressure exerted outwards by the air inside a balloon is roughly equivalent to the pressure exerted on the balloon by the outside, it remains inflated. This only holds true when the air pressure of the air originally put in the balloon is similar to the ambient air around it, however. If a balloon is filled with air from the upper atmosphere, then brought down to sea level, it will shrink, while if it filled with air from sea level and brought to a very high altitude, it will pop. This is what happens to balloons that are accidentally released into the sky.

Air remains in the Earth's atmosphere because the gravity of the Earth is sufficient to hold gas particles close to its surface. Lighter gases, such as hydrogen, have long ago escaped from the Earth's pull, being light enough that thermal excitation is sufficient to them to escape away into space.

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pastanaga
Post 10

@anon130321 - I think that there probably is some tiny amount of hydrogen lost to space, but it's probably not a huge amount.

Hydrogen is very reactive so if it did get released into the atmosphere, it would quickly bond with oxygen and become more water. I imagine the hydrogen that is talked about in the article probably escaped before the layer of oxygen developed, as that layer only developed relatively recently in terms of the Earth's existence so far.

irontoenail
Post 9

I recently heard of a study that likened people in a crowd to the molecules in a gas, and mentioned Boyles law. It was a study done in order to reduce the damage that can happen in places with massive crowds, like a concert.

They found that the same kind of rule applies, where, if the people are crowded into a smaller space, the pressure increases. Which sounds kind of obvious when you put it like that, but they are hoping by putting it into real calculations they will be able to reduce the numbers of deaths that occur from trampling and so forth by arranging the areas more efficiently.

anon130321
Post 3

Is there a fixed amount of water on the planet or is there natural process by which some of it is broken into it's constituent gases, allowing free hydrogen to escape from Earth's gravity?

Amphibious54
Post 2

@ anon23898- Climate is affected by the relative composition of the greenhouse gases. The greenhouse gases are water vapor, nitrous oxide, ozone, methane and carbon dioxide. These compounds play the role of absorbing and emitting solar and heat radiation. Too much of these compounds can block the transmission of gases back into space, causing the planet to heat up. Too few of other greenhouse gases like ozone can cause a situation where not enough solar radiation is blocked, leaving the earth's surface vulnerable to the sun’s ultraviolet radiation.

Greenhouse gases are not all bad. If these greenhouse gases did not protect the earth, too much radiation would escape back into space and cause the earth's temperature to plummet. If we did not have these greenhouse gases, the earth's temperature would be about 60 degrees Fahrenheit cooler, making it uninhabitable for humans.

anon23898
Post 1

what are the components that affect the climate of an ecosystem?

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