Observe: Proof in the Air

The previous activity explained how our air is a mixture of various gases.  The air around us is mostly nitrogen and oxygen. Smaller amounts of many other gases that we know about such as argon, methane, and carbon dioxide are in the air, too.  Because we cannot see, smell, taste, or touch these gases, how do we know they are really there?  Can we prove these gases actually are in our air?

Although we cannot see these gases directly, we can see the effects of them in the world around us.

  Everyday Connection

Unsplash

       

Breathe gently on a mirror or blow into the air the next time it is cold outside. Do you notice the fog that forms? You actually breathe out water vapour (which is a gas) but it changes to liquid form when it is cooled rapidly. You actually can see the water vapour you breathe out into the air when it’s cold outside.