Static Electricity Still A mistery

Static Electricity Don't try explaining this to children. We don't even fully understand it yet. Just call it "magic."

 Today in the Things We Thought We Understood But Really Don’t file, a Northwestern University researcher has upended what was previously thought to be a pretty good understanding of how static electricity works. Static electricity goes beyond the usual theory that it's a simple imbalance of charges caused by the exchange of ions, the researchers’ paper says. Rather, it is the result of anactual transfer of material.

             Static electricity has been under investigation for a few millennia now, with research dating back to the ancient Greeks. But the Northwestern team wasn’t convinced that everything was as it seemed. So they applied Kelvin probe force microscopy to the problem, which allowed them to see the varying levels of charge distributed unevenly across the surface of objects.

           What they found is that these charges are far less uniform than previously thought, and that clumps of positive and negative charge are strewn unevenly across surfaces. It’s these clumps that are transferred between objects when they come in contact, not just the charges. 

           In normal human language, that means that when you rub a balloon on your hair to make it stand up, there is a small exchange of matter--tiny bits of balloon actually adhere to the hair, disrupting the electrical patchwork on the balloon and causing that strange attraction between it and other objects that we all know as static electricity.

          That matter exchange is proven pretty definitively by this research, but like most discoveries, this one begets more questions. Why do these negative and positive clumps exist, and does knowing that they do exist fully explain the static phenomenon? Scientists still aren’t sure. And that, boys and girls, is why we never stop learning.

by "environment clean generations"

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Posted in: charges,electricity,objects,static,surfaces

Cloudy Days Can Still Burn Us

One of the most complicated problems in climate science is slowly but surely becoming a little better understood. The influence of a warming climate on clouds -- and the impact of clouds on climate -- is one of those puzzles that has had climate modelers scratching their heads for years.

             There are different daytime and nighttime responses to clouds as the Earth heats up and then cools down. There are different inputs from different cloud types, based on their height and structure in the atmosphere. There are global net effects and different local and regional ones as well. But the truth is, because clouds are often relatively small and ephemeral features, the big global models are almost blind to their existence.

             Led by atmospheric scientist Evgueni Kassianov, a research team from the Department of Energy's Pacific Northwest National Laboratory took a bunch of ordinary summer days in the flat landscape of Oklahoma and some everyday white billowy cumulus clouds and examined in unprecedented detail the sunlight they were casting about.

            The clouds cast cooling shadows irregularly over the land, of course, and their bright white surfaces reflected some sunlight back into space, another cooling effect. But their water droplets and aerosols scattered sunlight between their irregular surfaces and down across other clouds' shadows -- causing a significant warming effect.

            Sunlight scattered from cumulus clouds accounted for roughly 15-20 percent of the sun's heat reaching the ground on a cloudy day.

            While the net effect of clouds on sunlight reaching the ground is usually negative on cloudy days, Kassionov said the study "demonstrated that for days with cumulus clouds there are many cases (about 20 percent of total population) with positive cloud effect. And this effect is associated with cloud-scattered sunlight."

"We all know that we can still get sunburned on cloudy days," said Kassianov. "This explains why."

by "environment clean generations"

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Posted in: clouds,sunlight,surfaces