Yes! There's actually lots of different kinds of solids in the air
we breathe. It's important to understand, though, that the air itself
is /not/ made of solids. The oxygen, nitrogen, carbon dioxide, etc.
that make up most of the air are very definitely gases (this means that
the molecules of these things are not stuck together). But there are
lots of other things that float around in the air.
For example, if you've ever looked at the air just the right way
into the sunlight, you've probably seen dust floating around. Dust is a
solid that's made up of lots of other kinds of solids. You may have had
friends who are allergic to pollen in the air. Pollen is a solid that
comes from plants during the spring and summertime. There's also all
sorts of bacteria and viruses in the air - this is an easy way to catch
a cold if you're around someone else who has one. Little tiny bits of
dirt and rocks and whatnot float up into the air off of the ground. If
your mother is cooking dinner and accidentally burns it, there's
probably going to be smoke (burnt bits of dinner) in the air. And
anywhere that there's people or animals, there's bound to be a whole
lot of dead skin cells in the air that are rubbed off of people's skin
It's not that gravity doesn't pull on these small little things.
What happens is that they're so light that it doesn't take very much
for them to be moved. So if a little tiny bit of wind comes by, they
get blown up into the air, as if you were to blow on a pile of flour.
But many of these things will eventually settle down if the air is
still enough - like in a closet that nobody's opened in years. Then
everything gets covered with a layer of dust and all sorts of stuff
from the air. (But usually it all floats back up again as soon as you
open the closet to look at it.)
Hope this answers your question!
(republished on 08/01/06)