Sometimes we don't really see what our eyes are viewing. That's true with your computer screen, and it's true in nature as well. Oh sure, we can say what we think we're seeing, but we're missing the big story such as the man behind the curtain, to recall a famous phrase from an even more beloved movie.

For instance, it's a beautiful day here in St. Louis. The temperature is warm but not hot, there's a breeze gently wending its way through our offices, and the sun is out but not blinding. A few clouds are drifting across the sky. All in all, a perfect spring day.

A few days ago, however, I stood on the front deck of my house and watched a line of angry gray clouds sprint across the sky heading northeast. There was literally a line of demarcation in the sky: on one side was the remainder of a blue sky, running as fast as it could to flee from the dark thunderstorm chasing it along. As I watched the storm approach, I thought about one of the most fascinating bits of weather trivia I ever heard: the weight of rain clouds in terms of elephants [ABC has unfortunately removed the 2003 news article - Ed.].

Every cloud is made up of moisture, of course. On a day like today, a single fluffy cloud contains about 550 tons of water. Your average elephant weighs about six tons, so that means that those happy spring clouds are equivalent to around 100 elephants.

A bigger storm cloud, more like the one I saw barreling into the area recently, is more like 200,000 elephants in terms of weight. That's quite a jump, and it's kind of humbling, funny, and awesome to think of 200,000 elephants stampeding across the sky.

No such emotions attach to the numbers associated with a hurricane, however. Instead of awe or humor, now we're talking absolute terror. Instead of 100 elephants, or even 200,000 elephants, the water in a hurricane is equivalent to 40,000,000 - yes, forty million - elephants. Forty million elephants in the sky, bringing destruction and fear. Forty million elephants.

Next time you look at a cloud, think about how many elephants are in it. You had no idea that a cloud was so massive, and no idea that a creature so huge and seemingly earth-bound can be used to understand something so apparently light and ephemeral, did you?

And that brings us to virtualization software. You don't necessarily see what's really there.

Virtualization software

Virtualization software allows you to run multiple operating systems on one machine at the same time. Yes, that's a gross simplification, but let's keep things simple. If you're really interested, Wikipedia gives a good overview of virtualization that will help clear things up, or read the explanation offered by VMWare, one of the leading companies in this area.