Introduction to our Atmosphere



Hold you hand in front of your face, and breath deeply in. Now gently blow outward towards your fingers. What do you feel? Does it feel cool and tingly? What you felt blowing past the tips of your fingers is commonly referred to as air.

Air is one of the primary things that makes life on Earth possible. But what is air, and do all planets have it? Air is a synonym for atmosphere. The Earth’s atmosphere or air is made up of a variety of gases and other particles. Most of the planets in our Solar System, and even some of the moons have atmospheres. However, the atmospheres of these planets and moons are very different from that of the Earth.

The atmosphere of our home planet is made up of three primary gases. These gases are oxygen, nitrogen, and argon. In addition to these three gases, there are many other gases in the atmosphere, in trace or small amounts. Additionally there are small particles, or particulates floating in the atmosphere, such as dust, water, and pollen

As you blew air past your fingers, did you see anything? Air is invisible, tasteless, and scent free. The particulates floating in the atmosphere are however another story. Smoke is one type of particulate that commonly pollutes the atmosphere allowing us to see the air. Other particulates that allow us to see the air might be steam, dust, or in extreme cases, even pollen. Try this experiment. On a quite afternoon find a window where sunlight is shinning through the glass down onto the floor. Lay down beneath the window, and look up through the light. What do you see? Can you see the sunlight reflecting off of the particulates in the air? You should see dust particles, as well as tiny hair follicles. In addition to the particulates that are visible, there are many more that are not. They are too small to be seen by human eyes. These particulates are around us each and every day, though we usually do not think about them.

Why Is The Sky A Light Shade of Baby Blue?

This is one of the first questions that children often inquire of their parents. What makes the sky blue? Why is it not red, pink, or green? The answer to this question can be found by looking at the particulates floating in the air. The Earth’s atmosphere is filled with trillions of tiny dust particles. Most of these particles or particulates are too small to be seen with the human eye. The smallest particulates are by coincidence the same length as the wavelength of blue light. 

As the light from our Sun shines into the atmosphere most of the colors are able to reach the Earth’s surface uninterrupted. However, because blue light has a wavelength that is the same size as the particulates in the air, this light is scattered in every direction. This blue light bounces from particulate to particulate until it eventually reaches your eyes. For this reason, no matter what direction you look in the sky, it appears to be blue. This blue light originated with the Sun, was bounced around in the sky many times, and then eventually reached your eyes.

(Mrs. Ghosia Snober)



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