If like me, you imagine an electric generator to necessarily like a kind of gas works, full of turbines, which turn tricks, magnets or chemical reagents, I invite you to take a look at one's Lord Kelvin invented in 1857. It is simply water that flows gently into metal containers after passing through metal tubes equally immobile
Well, you do not risk the electric shock, but this funny marchin water still manages to give birth to beautiful spark, check out:
Magic? Not at all, the same principle is surprisingly simple. The two metal containers and tubing also normally neutral. But there's always one that is very lightly loaded. Suppose it is the right vessel and left tube that is positively charged:
This time, the right tube attracts the positive ions (H30 +) of water over him and drops that fall on the right are positively charged. The right container is positively charged and in contact with the left tube as well. A cycle begins and gradually increasing the difference in costs between the two containers until the voltage causes an electric shock.
A As the unit is charging, the jet splashed more and more about him and the droplets trajectories increasingly bizarre as to defy gravity!
Again, it is logical: the charged droplets are attracted to the tube (opposite charge) and added to the electrostatic force gravity. Very small droplets eventually just follow the lines of electrostatic fields
If a drop hits the tube that attracts, it unloads a bit: this phenomenon (among others) that limits the power of this type of electrostatic assembly ...
The simplicity of the assembly is impressive, but what fascinates me most is the spontaneous breaking of symmetry in the assembly. In the initial state the two containers are indistinguishable while at the end is one of the two positively charged without being able to predict which one. The waterfall (balanced) causes a cascade electrostatic totally asymmetrical.
one cascade to another ...
This cascade-breaker-of-symmetry reminds me of the enigma of 'homochirality of life ": the first Pasteur discovered that all the amino acids in living matter have the same configuration right propeller (like a corkscrew right-handed). Yet when synthesized in the laboratory these molecules, we obtain in general two types of propellers in equal amounts. This discovery made by Chance is fundamental because it marks the boundary between the living world and that of the inert in the living world there is only one size organic molecule from the two possible.
artificial molecules have yet exactly the same chemical properties in terms of density, melting point, etc.: why on earth is there only one configuration in nature? The mystery is far from being solved and the literature abounds with hypotheses from simple to more complicated (some refer to the spontaneous breaking of CP symmetry of weak interactions or to the effect of space radiation ).
One thing is certain living organisms, each made up of amino acids in helix only right, react differently to the two molecules format. Pastor had noticed for example that only the natural form of tartaric acid was digested by micro-organisms. We know he is with the molecule of vitamin C. Aspartame is sweet, but his twin mirror has a bitter taste. One could multiply examples infinity.
Shapes left (S, teratogenic) and right (R, sedative) of thalidomide (source CNRS)
This second discovery inspired him to Pastor a simple explanation for the strange consistent patterns of living: our living world would operate as a gigantic factory screws and nuts, which only the parts having the same meaning threads are compatible.
Although both types of molecular configuration may have existed in the original soup of life, the machine Kelvin can get an idea of who was able to move to the origin of life: just as the generator of water, a small imbalance between the proportions of the two types of molecules could trigger a cascade effect evolutionary resulting in the complete disappearance of one of two forms.
If this hypothesis is correct, do not look for special cause the propeller to the right, any more than we should seek to understand why this is the right vessel at one point that is positively charged in Kelvin's machine. Both types of physical stunts, and scalable break the symmetry original way that is both inevitable and unpredictable.
Oh by the way, I just realize that the term "chirality" (the property of a molecule can exist in two forms mirror each other) was just invented by Kelvin ...
Sources:
MIT Course 02.08 Walter Lewin on electromagnetism, a model of pedagogy!
The Ambidextrous Universe by Martin Gardner
An excellent summary of John Philibert on symmetry in nature ( pdf)
Related posts
Laterality animal on the origin of both right and left in the animal world
Game reflection on a mirror symmetry in
0 comments:
Post a Comment