What do breath and clouds have in common?
Breathing out into cold air will create visible breath.
Similarly, a giant standing on Earth pumping air from the ground to the very cold Troposphere could reproduce the fluffy cumulus clouds of a warm summer's day. This same giant's breath directed skywards could also produce clouds.
Why is that? Is breath really a microscopic cloud? Cold misted breath certainly looks cloud-like.
However, there are some differences between misted breath and clouds.
Why can we see cooled down breath as clouds?
When the sun warms up the water in our oceans and lakes, a small number of water molecules change from liquid to gas. These gas-state water molecules are water vapor. Each gaseous water vapor molecule is lighter than the nitrogen and oxygen molecules in air. They rise up towards the upper Troposphere.
The gaseous state water vapor molecules remain separated until they cool down. They are then connected into a web of cooled down water vapor molecules. Imaging a mesh of water vapor molecules forming high up above our heads. This mesh is invisible, as water molecules are exceptionally small. This is the first step to forming cold breath and clouds.
Breathing out clouds of Invisible versus visible water vapor
In a cold environment, water vapor molecules move from an invisible state (warmer) to a visible one (colder).
- Invisible Warm water vapor ---COOLING ----> Visible
- Visible Cool water vapor --WARMING----> Invisible
A floating ghostly mass
The thing is that when water molecules cool down they form hydrogen bonds as I noted above. Those are the bonds that allow one hydrogen atom to connect two larger atoms together (in this case two oxygen atoms).
Cooled down and interconnected water vapor molecules create a web that ensnares air bubbles. Basically an instantaneous spider-web-type of netting made of cooled down and connected water vapor molecules.
Air bubbles create scatter which reflects white light. The result is that the enmeshed air molecules within a web of cooled down water vapor molecules show up as floating ghostly mass.
What about water droplets within clouds?
If clouds are a web of strongly attracted hydrogen bonded water vapor molecules, what about all the droplets of water that we know also exist within clouds?
Clouds form through a multitude of compounding factors:
- cooling water vapor is only one of those factors
- pressure effects of two high and low-pressure fronts bumping or crashing into each other
- Changing temperatures and winds
- Changing day/night temperatures
- Ongoing addition of warmer water vapor that is rising from the earth's water surfaces
- Multiple particles (dust, salts, other ions) within the mass of clouds allow for water vapor condensation
All those factors play a role in condensing a bunch of water vapor molecules. Condensation is the process of water vapor molecules coming together to form liquid water. This condensation coalesces water vapor into minute water droplets.
How do clouds hold so much water?
Clouds are masses and masses of cooled down water vapor nets encircling droplets of liquid water as well as air. Visible clouds are massive entities.
One average sized cloud 1-kilometer long x 1-kilometer high will contain 500 million grams of water (or 500,000 liters). That's a lot of water.
To have a visual representation of that much water: A football field lined with 2-liter bottles side to side across the whole 360 x 160 feet breadth would give the equivalent of 500,000 bottles or 1 million liters of liquid.
How do clouds hold so much water without falling on our heads? It is because the usual droplets are microscopic and spread throughout the cloud. Their mass is still lighter than the mass of the air below them.
Breath and clouds
Contrast the water in clouds with that in our breath. One breath contains 0.014 cc (= grams) of water (on the average, we exhale 400cc of water in 24 hours, almost half a liter). This is about 1 tablespoon each hour.
In other words, the slightly more than 1000 breaths that we breathe each hour will fill up that one tablespoon of water!
Are we breathing out a cloud? Yes, as both clouds and our breath are part of the same initial process: Cooling down water vapor molecules to ensnare air pockets and water droplets.
Clouds are just a little more involved.