SPHERES

The other day, I was thinking about the air I breathe.  What would we do without it?  Before I get all choked up, let me tell you what I know about it.

Oxygen makes up only 21% of the air we breath.  78% of our air is nitrogen.  This adds up to 99%;  Argon gas is most of that other 1%  and what we exhale and fart make up about 0.05%.  This is our atmosphere.

The first thing you may ask is, why are we so worried about oxygen when it seems most of what we breathe is nitrogen?  It's because our bodies need oxygen and not nitrogen.  Our lungs transfer oxygen from the air to our blood and our blood takes it to all parts of our body.

Did someone ask why we don't have a more oxygen rich atmosphere?  Oxygen is less stable than nitrogen - it is an explosive and fire risk without the nitrogen.

Another component of our atmosphere is the density of the air.  It is most dense at sea level and progressively less as we rise above it.  When we climb a mountain or fly aloft in a hot-air balloon, the air gets less dense.  We have to breathe in more deeply or more often to get enough oxygen to satisfy our body's needs.  People who work or play at high elevations must acclimate themselves, that is, train their bodies to operate with less oxygen.

This is the first of a series!