Air is something that we can only feel and cannot touch. We can breathe air but cannot eat it or taste it. Air is completely invisible and inevitable. It plays the most important part in our life that is essential for breathing. So, what makes this air so important? In this article, we discuss the definition, properties of air, and composition of air.
Definition of air
Air is a homogenous mixture of different gases like oxygen, nitrogen, water vapor, carbon dioxide, etc. Air itself exists in gaseous form. We can feel the movement of air in the form of wind. You can feel the wind as you travel in a vehicle or stand near a coastline. Air can be stored and is very vital for our breathing. Life does not exist in outer space due to the absence of air. The atmosphere of the earth contains air. Different types of gases are present in the air.
Properties Of Air:
- Air is colorless and odorless
- Air can be felt
- Air is made of gases
- Air exerts pressure
- Air occupies space
- Air has mass
- Air expands
Now let us discuss each of the properties of air in detail with some examples. For more interesting properties of air, you can read this article by NASA.
1. Air is colorless and odorless
Air does not have any color of its own it is transparent. It neither has any smell of its own. But sometimes some gases mix with air to give us a good or bad smell.
2. Air can be felt
Air can only be felt like the wind. It cannot be seen or tasted but can be breathed. The air that goes into our body carries in oxygen and the air that comes out carries out carbon dioxide gas.
3. Air is made up of gases
Air consists of a number of gases like nitrogen, oxygen, water vapor, argon, carbon dioxide, etc. The compositions might vary according to local conditions like volcanic eruptions, factories, and other human activities.
4. Air exerts pressure
Particles of airflow in all directions and force are exerted which is called pressure. The closer we get to earth the atmospheric pressure increases due to the weight of air particles.
This force of air can also be seen in the form of air resistance when an object tries to move relative to air. This is also called drag. You can read this article “50 examples of friction” for examples of air resistance.
5. Air occupies space
Air, when blown, fills up the empty space therefore they occupy space. You can see this in the example of blowing a balloon. The more air you blow the more it will expand due to the volume occupied by air.
6. Air has mass
There is a misconception that air might be a massless object. But, the air has weight and due to the gravitational pull of Earth, the air present on the surface of the Earth is denser than at high altitudes. That is why you find it difficult to breathe at higher altitudes.
7. Air expands
Air has a property to expand, on heating it expands and occupies space the more it expands the thinner it becomes.
Composition Of Air:
1) Nitrogen (N2):
About 78% of nitrogen is present in the air. It is a very vital component of air. It is inert in nature which is why it doesn’t affect us even though ~80% of the air we breathe is nitrogen. It is a very important component for plants and is fixated and recycled through the geochemical nitrogen cycle. If air does not have nitrogen, then oxygen will burn everything, that’s one big blessing of nitrogen in the air.
2) Oxygen(O2):
About 22% of oxygen is present in the air. It is a vital component for sustaining life on planet Earth.
3) Argon(Ar):
About 1% of argon is present in the air. It is another inert gas.
All these major gases (nitrogen, oxygen, and argon) make up around 99.6% of dry air in the atmosphere.
4) Other gases
The rest 0.4% of air is covered by other minor gases like Carbon dioxide[~0.4 %], Neon[~0.08%], Helium [~0.005%], Krypton[~0.0001%], hydrogen[0.00005%], and trace amounts of xenon gas.
Other components in the air include Sulfur dioxide, methane, ozone, nitrous oxide, nitrogen dioxide, iodine, carbon monoxide, and ammonia
Which property of air is most important for us?
All the properties of air are important for us. Like, if there was no air pressure then the whole planet would be destroyed, so this property of air is very critical. You can read this article for more details on how this happens. And if the air was not made of gases then we would again perish and our planet would be something similar to a moon or like the other planets.
