We wouldn't be here if it wasn't for the atmosphere.  Not only does it protect us from most ultraviolet rays and meteorites, but all weather occurs in the atmosphere, usually in the lower part called the troposphere.  It holds the world's free oxygen and nitrogen gas (free in this case means in gaseous form) and keeps the earth at a temperature where life could begin and prosper. 

The composition of our air.
Notice the percentages of each type of gas.

Notice the tiny percentage of carbon dioxide gas (CO2) in our atmosphere.  Any percentage much higher than this figure would poison all life.  Plants use CO2 and give off free oxygen as a waste product.  We humans and other animals breathe in oxygen and exhale CO2, the exact opposite of plants. 

There would be no life on this planet without the atmosphere that we have.  Study the exhibit below, which shows how the atmosphere processes the sun's energy, to understand why.

How the atmosphere absorbs the sun's energy.
Most of the earth's energy, in some way, emanates from the sun.

Air gets thinner (fewer air molecules) as you go higher up.  Look at this exhibit (below) carefully to understand the immensity of the atmosphere.  Also, the atmosphere is made of invisible gases so you can't see it.  What you do see are clouds or particles that have become charged by the sun such as aurora borealis. (Northern lights)

The structure of the atmosphere.
Notice that almost all weather occurs in the troposphere.

Read the poem below to gain a full appreciation of the importance of the atmosphere for all life on earth.


The earth’s atmosphere is a mystery to me,

And no life on this planet would there ever be,

If we did not have this awesome, magical and gaseous shield,

A burnt wasteland would there be, rather than a beautiful field.

Earth’s atmosphere goes up for many miles,

Which causes air pressure like molecules in a pile.

At sea level, you have the most molecules of air.

As you go higher up, air molecules become more spare.

The atmosphere protects us from radiation(1) and meteorites.

Thank heavens for this or a lifeless planet would be our plight.

Nitrogen and oxygen(2) are the two main gases in which the atmosphere is comprised.

Scientists are still not exactly sure how the atmosphere formed so they must theorize.

Weather is generally caused by temperature and pressure change,

Occurring ten to twenty kilometers from the surface do these forces range

The earth’s atmosphere was formed as the earth cooled.

There was as yet no life and no humans around to rule.

Slowly plants came around and using carbon dioxide gas,

Fortunately had no use for the oxygen part and let it pass.

Breathe in that waste product which is given off by plants.

It’s called free oxygen, and life to animals does it freely grant.

Now exhale, and comes from your lungs carbon dioxide gas,

Which plants use in photosynthesis, just like the outside grass

To produce the energy it needs to make its very own food,

Working along with water and sunlight, how clever and shrewd.

It’s a circular relationship, opposite but can you also relate,

How one depends on the other, nature’s plan and our fate.


1: Radiation-Energy transmitted by waves through space.

2: Nitrogen and Oxygen-The atmosphere is about 75% nitrogen and about 20% oxygen. It also contains water vapor, ozone, neon, helium, carbon dioxide, argon, methane krypton, and nitrous oxide, all in tiny amounts. (With the exception of water vapor.)

CLICK HERE FOR ATMOSPHERE WORK SHEET. science available and comprehensible to the masses.