Air is a form of matter that constantly surrounds us, filling our lungs, homes and extending for miles above the Earth’s surface. However, if we look around, the air is invisible. Why can’t we see the air? The answer lies in the properties of light and the composition of the air.
Air is a mixture of various gases, mainly nitrogen (78%) and oxygen (21%), along with traces of water vapor, argon, carbon dioxide and other compounds. These gases are made up of molecules so small and dispersed that they cannot scatter light in the same way that larger, denser particles can.
Light, part of the electromagnetic spectrum, interacts with matter in various ways: it can be reflected, refracted, absorbed or scattered. What we see is light reflected or scattered to our eyes, explains Science Notes.
Why can’t we see the air? In the case of air, the molecules are so small that they do not effectively scatter or absorb visible light. Therefore, most light passes directly through air, making it invisible to our eyes. However, air is not completely transparent over the entire electromagnetic spectrum. For example, it absorbs some of the ultraviolet, infrared and X-ray light. Not coincidentally, human eyes do not perceive these types of light. Our vision has evolved to give us the best visibility in our surroundings. Although we cannot see the air directly, there are ways we can observe it indirectly.
Why can’t we see the air? Ways we could see it
Scattering of light: Although air does not effectively scatter visible light, it mostly scatters light with short wavelengths such as blue and violet. This is why the sky appears blue during the day.
Air Effects: We can observe air effects such as air movement. When we see the leaves of the trees rustling, they are being moved by the wind.
Condensation: When air cools, water vapor condenses into tiny droplets, forming clouds, fog, or dew. These droplets are large enough to scatter light and become visible.
Pollution and dust: Small particles such as dust, smoke, or airborne pollutants can scatter and absorb light, making the air appear hazy.
Compression and Heating: Air becomes visible when it is compressed or heated. For example, air in an optical illusion (mirage) becomes visible due to the refraction of light by the heated air. The distortion we see above a hot road on a summer day is an example of visible air due to temperature differences.
From space: Earth’s atmosphere appears as a thin, blue halo when observed from space. This phenomenon is caused by the scattering of sunlight, known as Rayleigh scattering. Blue and violet light are scattered more than other colors because they have shorter wavelengths. This scattered blue light is what we see when we look at the sky.
In conclusion, although air seems invisible, through various natural phenomena we can observe its effects and presence.
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Source: www.descopera.ro
