Monday, June 02, 2008

World Wonders #2: Wind and Spin

I was tracking my MINI, and looking at the wind directions on the map. Then it struck me, I don't know where wind comes from! So I look it up:

Wind comes from
1)Earth's Rotation: as earth rotates, air does not move exactly at the same speed the earth because of fluid properties like viscosity. Its kind of like feeling the wind when you're going in a car, but the air isn't blowing that hard; its the car moving into the air.
2)Thermal properties: we all know hot air flows to cold air. The sun heats the earth unevenly. Most of it hits the equator. So the air from the equator naturally circulates towards the poles, where it is colder.

Then I thought.. why does the Earth Rotate? I thought it was because of gravity of the sun so that Gravity+Heat= Wind! but I was wrong.

Apparently Earth spins because there is nothing stopping it from slowing down. There is no friction in space, and I guess the air drag is so miniscule compared to the mass of the earth that it is insignificant. I also read something about the moon's tidal wave drag, which is also insignificant.

The Earth and all other planets started spinning because that is how they were formed. Dust clouds swirled into itself due to its own gravity and began to form planets. As the cloud condensed, the matter spun faster and faster. It's kind of the technique that ice skaters or breakdancers use when they spin. Arm's out, spin slow. Arm's in, spin fast. So the Earth was spinning initially, and it just can't stop! maybe in a bajillion years.

Sources: Kid's websites!

1 comment:

Fishy said...

Wow, I actually never thought about that. For some reason I just took wind for granted. Good info.