DE RERUM NATURA: ELECTRIFYING AFFAIRS
MANILA, JANUARY 24, 2008 (STAR) DE RERUM NATURA By Maria Isabel Garcia - A man in his prized vacation spot somewhere in the Baltic Sea has recently been awarded the kind of award no one gets while alive. And he was no exception. This involved the Darwin Awards (www.darwinawards.com) — those given annually to those who improve the human gene pool by accidentally removing themselves from it. The man was given the award because of his fatal determination to carry out the maximum measure to exterminate a mole (a kind of big rodent) that lived underground in his property. This measure took the form of installing some metal rods which he, shall we say, rudely awakened, by connecting them to a high voltage power line. As a surprise to only himself and to potential Darwin awardees, he electrocuted himself and died. When the police arrived, they had to trip the main circuit before they could inspect the scene surrounding the yet to be awarded individual.
Inspired to do a postmortem on the incident, I thought it would be good for us, especially those who bear such astounding potential to be Darwin awardees, to know what “conduction” is when it refers to electricity and why it can cause many things, including death, to many life forms, including moles and humans. And while we are it, maybe it would not hurt to wander into their cousin concepts such as “semiconducting” so we would better appreciate the micro electrical rhythms — the notes and the rests — inside our computers that gives the electric soul to this information age. We will also go into something very strange called “superconductivity.”
Everything is made up of atoms. Electrons are inside atoms. In some things like glass and plastic, electrons cling very tenaciously to their atomic home. But in other materials like metals, electrons are positioned as such that they can be “friendly” to each other (as in metals like copper), that when voltage is applied, as our Baltic man found out, the electrons move and this movement is called electric current. Materials that enable electric current to flow when voltage is applied are called conductors. Those through which electrons cannot pass through freely are called insulators. Water and salts (not just the salt you are familiar with in the food you eat or drink but all kinds of salt, including the ones found in soil) are also conductors of electricity even if they are not metals. Your body, like the Earth, has a lot of water in it and while this watery feature enables you to be the recipient of a lot of life-giving substances, a high dose of voltage especially from a power line, will definitely give rise to the last spark you will ever see alive.
Semiconducting involves substances that are neither generous nor frugal with electrons but both, depending on what they are “on.” I say “on” because this process is called “doping,” when a material’s ability to conduct electricity is determined by its “impurity.” Silicon, the most common semiconductor, is “on” various “dopants” in order to do what it does. Another more interesting way that electrical current moves in semiconductors involves a process I can visualize as some kind of atomic sungka because it involves the movement of an electron leaving behind a “hole” where another can jump in but leaves another hole and so on and so forth. This process also makes for the play — the movement of electric charge. Semiconductors have enabled us to control such delicate flow of electrical current that with semiconductors, we have been able to miniaturize devices like phones and computers, and still continue to do so.
In conduction, electrons lose some energy when it bumps into atoms as it moves. This is called “resistance.” But there is another kind of “conduction” which completely throws out everything we know about “normal” conduction and it is “superconductivity.” This started with the cool experiment in 1911 done by Dutch physicist Heike Onnes when he dipped a wire into a really freezing bath of liquid helium (in the level of minus 273 degrees Centigrade or just four degrees above absolute zero). Later on in 1957, the mystery was explained in a 1972 Nobel-earning theory by three physicists, namely John Bardeen, Leon Cooper and John Robert Shrieffer. They found out that some materials, at these very low temperatures, do not have their electrons colliding with the atoms but rather they pair up like a mighty duet that otherwise would have been weakly soloists, and take on a singular character that could easily move through without resistance, like the fluidly cascading music of paired musical instruments that could penetrate and pass through the spirits of an otherwise impervious crowd.
If you have been through an MRI machine, you have met a superconductor because they are inside instruments like MRIs. It is nature’s habit to have electrical currents reliably producing magnetic fields so that having superconductors which can conduct without resistance would mean they are ideal for making electromagnets that are sensitive to the atoms in your body. This enables trained medical experts to use MRIs to have sliced photos of your insides. It would also be ideal to have means of transportation that could rely on superconductivity since it would make for vehicles that could run a lot longer since there would be no energy loss from electron collisions. But it takes a lot more energy to cool stuff to those temperatures to make them superconducting. The quest for the holy grail of superconductivity now for physicists is to find superconducting materials at room temperatures.
I do not know if brushing up on basic science lessons about electricity could have saved our Baltic man from winning the Darwin award. But I think, if he could not be a good example in life, he could at least be a horrible warning in death.
Chief News Editor: Sol Jose Vanzi
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