Posted: Sun Mar 02, 2008 8:18 pm Post subject: Reply with quote
Since air has weight it must also have density, which is the weight for a chosen volume, such as a cubic inch or cubic meter. If clouds are made up of particles, then they must have weight and density. The key to why clouds float is that the density of the same volume of cloud material is less than the density of the same amount of dry air. Just as oil floats on water because it is less dense, clouds float on air because the moist air in clouds is less dense than dry air.
We still need to answer the question of how much a cloud weighs. For an example, let's use your basic "everyday" cloud—the cumulus cloud with a volume of about 1 cubic kilometer (km) located about 2 km above the ground. In other words, it is a cube about 1 km on each side. The National Oceanic and Atmospheric Administration (NOAA) provides some estimates of air and cloud density and weight. NOAA found that dry air has a density of about 1.007 kilograms/cubic meter (kg/m3), moist air comes in at about 0.627 kg/m3, and the density of the actual cloud droplets is about 0.0005 kg/m3. The density of the cloud is thus about 62 percent of dry air. In the final calculations, the 1 km3 cumulus cloud weighs a whopping 1.4 billion pounds (635 million kilograms)! But the cloud floats because the weight of the same volume of dry air is even more, about 2.2 billion pounds (1 billion kilograms). Still, remember that it is the lesser density of the cloud that allows it to float on the dryer and more-dense air.
Ok, considering these guys and girls have the all tools to back this up, I think we can accept that:
1) Dry air is denser than cloud.
--> clouds must displace some amount of dry air
--> a cloud is a physically separate entity in the atmosphere
2) Water in a cloud is the "reason" the cloud is less dense than drier air
--> Opaque air is less dense than transparent but also moist air
--> normal air also holds water but is not a cloud, i.e. opaque
So, something (or the lack of something) turns normal moist air into an opaque cloud, which then floats on a pressure/plasma barrier like foam on a lake and in turn is capped under a pressure/plasma barrier under the stratosphere (like a thermocline).
What is it then that makes normal air go through a phase shift? Personally I think it is a sign of low plasma density. That is, there is a cloud lurking inside all of moist air. Under normal plasma densities, the cloud is contained like a popcorn kernel. Drop the plasma density and the air will "pop" into a cloud, which then takes on a life of its own.
As for ice in clouds this isn't so hard to accept either. Ice is less dense than water.
So if you have a separate atmospheric entity called a cloud- which is full of water, then the less dense water should float on the top.
--> Ice at the top.
It is only when the cloud lattice breaks down that you get re-crystallization, or "mineralization" of the water (remember, ice is a technically a mineral). Specific gravity is changed and you get precipitation.