What's in the Air We Breathe?

Your brain may weigh just two or three pounds, but it controls everything that your body does: eating and walking, to how you play video games, to breathing hard after playing soccer.

Take a deep breath. That's inhaling. Breathe it out. That's exhaling. Ever get a little tickle in your nose that made you sneeze? That may be some of that dust you see in sunbeams through your window. Or maybe it's a little bit of dandelion fluff floating in the air on a breezy, spring day. Or that little extra pepper on your mashed potatoes. Whatever made you sneeze, that sneeze threw it 100 miles per hour, sprinkling mucus particles over everything in its path!

• The Anatomy of Breathing See how we breathe in this animated video.

• What Made Me Sneeze? Find out what how complicated sneezing really is!

• The Sneezing Balloon See how easy it is to spread germs by sneezing.

The Cool Stuff is in the Science

Most people think that the air we breathe is simply oxygen. Air is actually made up of ten different types of molecules and atoms. These particular molecules and atoms are gases; and, they make up the air that particles like dust and dandelion fluff float in--what we breathe every single moment of every single day.

The Molecules: two or more atoms joined together. An atom is the smallest part of an element that retain its chemical properties.

• Nitrogen (molecule: N₂) makes up most of our air. Eight out of 10 molecules are nitrogen.

• Oxygen (molecule: O₂) the remaining two molecules make up our air, that's 20 percent.

• Carbon Dioxide (molecule: CO₂) without it, our trees and plants cannot grow. When we breathe out, we help the environment! Carbon dioxide makes up just three out of 10,000 atoms/molecules of air.

• Methane (molecule: CH₄) bacteria, natural gas and swamps all are sources of methane gas. Even certain gases that make a lot of noise after you eat chili with beans! Only two out of a million atoms per molecule of air is methane.

• Hydrogen (molecule: H₂) One of every two million atoms per molecule is hydrogen. Hydrogen is very flammable. If there were more hydrogen atoms in the air, would we combust?

The Inert Gases: nonreactive gases-also called noble gases-group 18 on the periodic table

• Argon (atom: Ar) used in light bulbs, argon is an inert gas, it makes up one of 100 atoms per molecules of air.

• Neon (atom: Ne) the same inert gas that lights of the colored lights in the mall; two of 100,000 atoms per molecule of air.

• Helium (atom: He) inert gas; five of one million atoms per molecule of air. Fills up balloons and is used by welders. 

• Krypton (atom: Kr) inert gas; one of one million atoms per molecule of air. Used in lighting. 

• Xenon (atom: Xe) inert gas; 87 atoms of one billion atoms per molecule of air. Makes the blue light in some headlights.

• Air Composition The molecules and the inert gases that make up the air that we breathe in terms older children can relate to.

• What's in the Air? Appalachian State University research project and video.

• The Periodic Table of Elements See where the elements in air are located on the chart.

• The Air We Breathe Is there any one particle in the air that causes ill health?

Wrinkled and Gray, Operation Central

Now we know the science of air, now on to the gray matter. What makes us breathe all those gases without thinking about it? The brain! It sends messages to the central nervous system, which sends messages to the nerves, which tells different body parts what they need to do in order to function. In this case, to breathe. If you don't breathe, you die. Simple cause and effect. The brain is the central processing unit of our bodies, much like a computer. Instead of millions of calculations a second, the brain helps us breathe around 16 to 20 times a minute, roughly about 20,000 times each day, depending on the person.

• Breathing and the Brain How the brain controls breathing. For older teens and young adults.

• The Nervous System and Breathing How the central nervous system works with the brain so that we can breathe. For older teens and young adults.

• The Brain Atlas What parts of the brain control breathing? Find them here.

• Brain Control The center of life. Controls the involuntary act of breathing as well as when we decide to hold our breath or release a breath.

The respiratory system helps the brain breathe. You breathe in through your nose. Did you ever look up into your nose in the mirror? Notice the little hairs in there? Those are called cilia. Cilia catches the dust and the dandelion fluff so it doesn't make its way down your throat into your trachea, or windpipe, through your bronchial tubes, ending up in tiny air sacs called alveoli in your lungs.

We've already mentioned that one of the gases that makes up air is oxygen. Our body needs oxygen to keep those millions of alveoli in our bodies alive and growing. No oxygen, our cells die. Those cells are filled with carbon dioxide. The oxygen and the carbon dioxide exchange places in a cycle called the respiratory cycle. Breathe in, in comes the oxygen. Breathe out, out comes the carbon dioxide. And the brain controls the whole process.

• The Respiratory System for Kids Discovery Channel's guide to why we need to breathe.

• The Process of Breathing Geared toward teens, this guide goes into detail about the respiratory process.

• Oxygen and the Lungs How oxygen and carbon dioxide exchange.

• How Dust Particles Cause Harm The subtle harm from breathing in too much dust.

• Respiratory Disease Depicts the importance of keeping the alveoli healthy through proper breathing.

• Artificial Nose Hair Inventor creates artificial nose hair to replenish lost nose hair.

Since the cilia catches most of the irritants that can get into our lungs, what can you expect to find if you inspected those little hairs in your nose besides dust and dandelion fluff? Bacteria and other microorganisms like germs, spores, pollen, and fungi, chemicals, even small bugs get caught in the thick hair and mucus. A neat experiment? Hang up some clear, double-sided sticky tape from a ceiling or a shelf for a day and see what gets caught!

• What do I breathe? Creating an "air junk" collector to capture and examine what shares our air space.

• Indoor or Outdoor Air Which has more particles. An experiment for grades four through six.

• Air Quality Experiment Testing the air by particle measure.