Thursday, February 12, 2009

How does heat travels

I was intend to check this-out "How does the heat travels".... When I give this phrase in google there were good direct proper results, few pages of NASA... and some properly explained pages...

I was interested to study this out, because I had a doubt raised in my mind when I saw, Al'gore presentation about global warming, he presents by depicting heat as a man, travels from sun to earth, wherein there exist matter less space in mid.

And he says further, when the heat entered reflects back as Infrared from the ground of the earth, because of CO2 presence the heat wasn't able to get out from our atmosphere and that's how the Global Warm increases tremendously in the last 15 years as CO2 presence was drastically increased in our environment in the last decade. He says the further threats, that the snow and glacier rocks may diffuse and can affect the hot and cold water flow in the sea and can increase the sea-level.

Coming to the point, the heat travels by three ways, conduction, convection and radiation

Conduction - This way of heat transformation happens in the solid objects.

Convection - This way of heat transformation happens in fluid and air. When we boil water before we take bath, this is what happens. It transfers the heat from warmer side to cooler side in the opposite direction of gravity.

Radiation - This is the way we are getting heat from our nearest natural resource - sun. It says the rays fall on electro-magnetic spectrum range [X-Rays, InfraRed, Light, Ultra-violet, Micro Waves, Radio] can heat an object. It happens by induction*. Even the visible colors spectrum falls on this range.



It clears me the other doubt too, US and even our country launches many satellite that goes totally out from our atmosphere, U.S. stretched upto Saturn (Cassini), and India now started with Chandarayan-I. So using these kind of waves fall on electro-magnetic spectrum, on certain frequency, these satellites communicates the local space station on earth. So it happens by induction*. That's how they communicate even though there is Matter Less space in mid. One amazing thing is that, sometimes cassini has to communicate to earth, intruding sun, if the saturn lies on the other half.

The following web pages can give good context of how heat travels/move...

http://coolcosmos.ipac.caltech.edu/cosmic_classroom/light_lessons/thermal/transfer.html

http://www.qrg.northwestern.edu/projects/vss/docs/thermal/1-how-does-heat-move.html

http://science.hq.nasa.gov/kids/imagers/ems/visible.html

--
Anand
anand.sadasivam@googlemail.com

*I've used the term induction even though it all propagate like waves, as I think some matter is required for any vibration (or waves or rays) to pass through. Hmm!! Maybe rays could be the right term, sounds like doesn't require any matter.