What We Knew About Static Generation Was A Myth
For centuries humans assumed the Earth marked the center of the universe. Then Copernicus came along, refused to accept this "common knowledge," and completely changed our understanding of the situation.
As children we are taught to accept that science is a body of facts based on well-researched evidence. We are not to question the Earth's place in the universe, the assertion that what goes up must come down. They are the irrefutable truisms of our existence.
Yet sometimes we do ask questions. We seek new proof. We ask what if? Recently a team of chemical and engineering researchers from Northwestern University did just this – they challenged our common knowledge and have quite possibly changed the face of contact electrification science forever (or at least until the next big discovery).
As children we find cruel pleasure in rubbing a balloon up against our head and affixing it to kitty's back, laughing with our friends as the feline uselessly attempts to escape the cohesive charge. As students, we look forward to that exciting day in which our science teacher brings in a Van de Graaff generator for the day's lesson. As lovesick adolescents, we await "the spark" of contact with a crush.
Static electricity is fun, interesting, sometimes even a little sexy. It's always seemed simple enough. Two objects come into contact – one has a negative charge, the other is positive. If they catch each other at the right moment or if enough friction is created between the two of them, zip! We have a static shock.
Another of our childhood proverbs applies well to this situation. Nothing is ever black or white. In this case, two surfaces are never uniformly positive or negative in charge.
Science featured a groundbreaking new article in their June 26, 2011 issue. I highly recommend accessing the full study: The Mosaic of Surface Charge Contact Electrification. In the meantime, allow me to break down the basic components of this new principle in a way which is easy to understand whether or not you have a PhD in nanotechnology. First a definition:
Kelvin force microscopy: a microscope which observes objects at the atomic level by measuring the interaction between the probe tip and the surface.
Rubbing materials together under the Kelvin force microscopy lens, researchers discovered that charges don't transfer uniformly. In other words, any given material is neither positively nor is it negatively charged. Every material has both charges. Picture a very large checkerboard, rather than having a patterned surface of black then white then black, the surfaces of materials have a jumbled mishmash of squares falling in no predictable order.
Let's take the example of checkers one step further to explain how this mosaic charge theory differs from the previously accepted model. A man and a woman play checkers. She takes a piece, then he. She captures another and another, ultimately winning the game.
By our previous understanding, we might say that the game belonged to the woman because she captured the most pieces, shifting the balance and the game her way. But what of the man? He played a good game too; in fact, he captured nine pieces before waving the white flag of defeat. If an interested third party wanted to hear about the game, would simply stating "she won" give him all of the information he wanted? No! He'd want a play-by-play, the most complete understanding of the interaction.
Perhaps the man made a genius move, hopping five of her pieces and claiming a queenship. At her best, she only got two of his checkers. And our surface is just the same, some pockets are up to one-hundred times stronger than the overall charge. Even though our man lost the game, he still made the best individual move. A third party watching the game might not remember her victory, but will instead chat on about his epic move.
The mosaic theory discounts a general charge for each surface, putting forth its patchwork model. Even if the overall charge of a surface is negative, an individual patch with a positive charge may, in fact, be the strongest.
Static electricity may not be as simple as we once assumed, but for those seeking fun, excitement, romance – you can tap into its sparks in the same exact manner as before. As for the patchwork model, these researchers have made their move. It's time for other scientists to make theirs so that we may determine which contact electrification theory will ultimately claim the victory of acceptance
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