In my other section "Light Scattering In The Sky" I touch on why clouds are white (governed by Mie scattering), but here I'd like to explore cloud physics more generally.

Clouds formation occurs under certain conditions - conditions that are well understood (but still studied!!) from physics. Through studying this formation, or using it to our advantage, we can learn fundamental aspects of our universe.  The discovery of the positron, the initial proof for 'anti-matter', came from using a cloud chamber to track the positrons path under a magnetic field. Even now more sophisticated 'clouds' are made in bubble chambers in an attempt to detect candidates for dark matter particles. This section will seek to explore and define the concept of a cloud, in all of it's wonderful manifestations. I hope it proves to be a rich source of material for us to explore together. 

To start, here is a video of me throwing water on my roommate. (Not what I was aiming for...but great results. :p) Note how one cup of water undergoes a phase transition (i.e. becomes a cloud), while the other cup is lame on doesn't transition.  Can you guess why?

Particle Detectors - The Cloud Chamber

The cloud chamber was one of the original particle detectors that was able to detect the original anti-matter: The positron (i.e. anti-electron).  

Making your own clouds!

I came across this article from scientific american that gives you one way to make your own cloud.  They use sharp changes in the temperature (similar to the video above), but there's another way.  Can you think of it? (Can you feel the pressure :p)