kookaburra
Sunday, December 10, 2006
Why the Sky Is Blue
by John Ciardi
I don't suppose you happen to knowWhy the sky is blue? It's because the snowTakes out the white. That leaves it cleanFor the trees and grass to take out the green.Then pears and bananas start to mellow,And bit by bit they take out the yellow.The sunsets, of course, take out the redAnd pour it into the ocean bedOr behind the mountains in the west.You take all that out and the restCouldn't be anything else but blue.Look for yourself. You can see it's true.
Why is the Sky Blue: A simple Explanation
The sky is blue for the same reason that everything that is blue looks blue, like blue ink or a blue shirt. You may think that air, the main sky / atmosphere component, is transparent but thick layers of air - a few kilometers or miles, like the atmosphere's width, are bluish due to small dust perticles. So the sunlight that passes the atmosphere air reaches your eyes blue like a beam of bright like passing some blue glass or filter.
But why are sunsets and sunrises red? Because at sunset times the atmosphere air is red? To understand this you may need some more advanced explanation described in the following chapter.
Science:Why is the Sky Blue
Spectrum of blue sky clearly showing solar Fraunhofer lines and atmospheric water absorption band.
Diffuse sky radiation is solar radiation reaching the earth's surface after having been scattered from the direct solar beam by molecules or suspensoids in the atmosphere. Also called skylight, diffuse skylight, or sky radiation. Of the total light removed from the direct solar beam by scattering in the atmosphere (approximately 25 percent of the incident radiation), about two-thirds ultimately reaches the earth as diffuse sky radiation.
Scattering is the process by which small particles suspended in a medium of a different index of refraction redirect a portion of the incident radiation in all directions. In elastic scattering, no energy transformation results, only a change in the spatial distribution of the radiation. The science of optics usually uses the term to refer to the deflection of photons that occurs when they are absorbed and re-emitted by atoms or molecules.
Why did the chicken cross the road?
Aristotle: It is the nature of chickens to cross roads.
Isaac Newton: Chickens at rest tend to stay at rest, chickens in motion tend to cross roads.
Albert Einstein: Whether the chicken crossed the road or the road moved beneath the chicken depends on your frame of reference.
Werner Heisenberg: We are not sure which side of the road the chicken was on, but it was moving very fast.
Wolfgang Pauli: There already was a chicken on this side of the road.
Saturday, December 02, 2006
Computer Virus Infects More Than 600 Files at LRDC
Recently, 600+ files on two LRDC file servers were found to be infected with the LoveLetter VBS virus, which spreads rapidly, infecting and renaming many graphic and audio files. Often, these files cannot be cleaned and must be deleted. Anyone who opens one of these files can continue to spread the virus through e-mail and shared files. Most times when an outbreak occurs, it is because a newly discovered virus cannot be detected using current definitions. However, the recent outbreak at LRDC is most unfortunate because the LoveLetter VBS virus has been detectable for several months. This virus would not have spread at LRDC if all computers were kept up-to-date.
It is not possible for our group to regularly update each computer as new definitions are released frequently. Last year, we developed an anti-virus plan that includes posting updates on LRDC's web site and file servers. We also asked projects to appoint a representative to oversee their updates. The recent outbreak illustrates how critical it is to check your anti-virus software regularly and apply program patches when available.
To check your definition date, Mac users must open the Virex program from the launcher or hard drive; the definition date appears at the bottom left of the screen. Win 9x/NT users must right-click on the Vshield icon at the bottom right of the screen and select About. The version, virus definitions, and scan engine should be equal to or later than those shown on the right. If your definitions are not current, call your project representative or Shari.
vocabulary: LRDC -Learning Research and Development Center
Shari- Shari Kubitz, project representative
