Major Components of the Atmosphere

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  • 0:07 Air Is a Mixture
  • 0:36 Atmospheric Components
  • 2:02 Greenhouse Gases and Ozone
  • 3:18 Lesson Summary
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Lesson Transcript
Instructor: Sarah Friedl

Sarah has two Master's, one in Zoology and one in GIS, a Bachelor's in Biology, and has taught college level Physical Science and Biology.

Our atmosphere is a complex mixture of many different gases. In this video lesson you will identify the major components of Earth's atmosphere as well as how much there is of each.

Air Is a Mixture

You may think that air is pretty simple, straightforward stuff. But this is far from true! Believe it or not, air is actually a mixture of different types of gas molecules. The components of air are important because they allow both plants and animals to breathe, trap heat on Earth (keeping it warm) and block harmful UV radiation from coming in through the atmosphere. However, these gases need to be present in just the right amount in order to do their jobs correctly.

Atmospheric Components

You may be surprised to learn that the most prominent gas in Earth's atmosphere is not oxygen. This is certainly an important component, but our atmosphere is in fact mostly nitrogen - about 78%! Oxygen is the second biggest player, making up about 21% of the atmosphere. Argon is next, but here we get another significant drop - only 0.9% of the atmosphere. Not even one percent!

There are several other components, but they occur in such small quantities that they're all grouped together as 'other gases,' and together they make up only 0.04% of the atmosphere. This other category contains components that you are likely familiar with: water vapor, carbon dioxide, helium, ozone, methane, hydrogen, neon and carbon monoxide, just to name a few. There are also particles floating around the atmosphere like dust and pollen, and these are such a small fraction that they are less than one one hundred thousandth of a percent.

These percentages may make it sound like there isn't much of anything but nitrogen and oxygen in the air, but it's important to remember that there is a whole lot of air up there! The atmosphere extends to over 300 miles above the ground and circles the entire planet. So while the 'other' category makes up only four hundredths of a percent, that still covers a lot of space.

Greenhouse Gases and Ozone

You may have recognized some of the gases in the list of 'other' components as greenhouse gases. This category as a whole makes up only a small fraction of the atmosphere, but just because they are small in numbers does not mean they do not play a large role. In fact, we should be glad that gases like water vapor, carbon dioxide and methane occur in the small amounts they do because they are such potent greenhouse gases. Like a thick blanket that covers Earth, they are especially good at trapping heat. And because their concentrations are increasing due to human activity, more heat than ever is being trapped underneath these gases and Earth overall is warming.

Ozone is also a small but very important component of the atmosphere. Ozone is made up of three oxygen molecules and is what protects us from harmful UV radiation coming from the sun. Ozone absorbs this radiation, blocking most of it from reaching us on the ground. This is why there is such a concern about the thinning of the ozone layer.

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