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Hi Folks,
As I was researching the story behind the different natural
isotopes of carbon, I came across the same situation I've found while
researching everything else (from the growing conditions of various unusual
plants I'm collecting to alternative treatments for my youngest daughter's
assorted medical issues and handicaps): The information on the many websites
that I find is all either incomplete, in conflict with each other, or just plain
out of date and wrong. I also find that rewording the search phrases will bring
up sites that would have been missed on the initial search and some of these
have been the most helpful. It definitely pays to be thorough and in order to be
thorough, you often have to be persistent and creative.
The story on the carbon isotopes... and the saga of what other
intriguing stuff it led to.... for those who are interested:
Carbon is the sixth most abundant element in the universe, or so
science believes (extrapolating from the very small piece of the universe that
we have personally examined). According to science, the top ten elements, in
order of abundance are: Hydrogen, Helium, Oxygen, Neon, Nitrogen, Carbon,
Silicon, Magnesium, Iron, and Sulfur.
Carbon 12 has six protons and six neutrons in its nucleus and is
the most prevalent form of carbon (almost 99% of all estimated carbon on
Earth).
Carbon 13 is a stable, naturally occurring isotope and makes up a
bit over 1% of the total carbon on Earth. It has six protons and seven neutrons
in its nucleus.
I found conflicting information over whether plants "prefer" carbon
12 over carbon 13; one site stated that it is so low in saturation that plants
just encounter the carbon 12 most of the time. Another site stated emphatically
that plants only use it if they can't get carbon 12. Plants can apparently
use both and also the unstable isotope; carbon 14. All three dissolve in
seawater and are found in the oceanic food chain in similar concentrations as in
the land-based food chain, as far as any of these sites knew.
Carbon 14 (also known as "radiocarbon). It is formed in the upper
atmosphere by a nuclear reaction between energy from the sun and the Nitrogen 14
atom. It has six protons and eight neutrons. It's mildly radioactive (beta
decay), but supposedly not dangerously so, and it has a half-life of
approximately 5,730 years. When it completely decays, it
becomes Nitrogen 14 again. This is the carbon isotope that is
used in "carbon dating" to estimate the age of some artifact or
fossil.
There are two other known isotopes; carbon 11 and carbon 15, but
they are so unstable they have very short half-lives. Carbon 11's half-life is
20.3 minutes and carbon 15's is 2.5 seconds. These are used for medical tests as
tracers in the human body.
In addition to information on isotopes (atoms that have the same
number of protons but differ in their atomic weight because of the number of
neutrons), I found information on "allotropes". Carbon atoms don't like to be by
themselves, apparently. They tend to form molecular bonds, even amongst
themselves. A molecule of one element is called an allotrope. Depending on how
the molecule is organized, the resulting properties of the material can be
radically different. Diamonds are one allotrope of carbon. Graphite is another.
They are atomically identical and differ only in the way the atoms are
organized. [If that's not sufficient proof that we
need to study the causal effects of organization in science, what the hell
is?!] There are currently several different
allotropes of carbon, although the websites differ in the number they offer. I
count nine, adding all the ones I found at different sites, without repeating
any. More continue to be discovered all the time.
Then, there's this little gem:
GrapheneFrom Wikipedia, the free encyclopedia.Graphene is a single planar sheet of sp² bonded carbon atoms. It is not an allotrope of carbon because the sheet is of finite size and other elements appear at the edge in nonvanishing stoichiometric ratios; a typical graphene would have the chemical formula C62H20. Graphenes are aromatic. Graphenes may consist of only hexagonal cells but if a pentagonal cell is present the plane warps into a cone shape; insertion of 12 pentagons would create a fullerene. Insertion of a heptagon causes the sheet to become saddle shaped; controlled addition of pentagons and heptagons allows a wide variety of shapes to be made. Graphenes are interesting because carbon nanotubes may be considered to be graphene cylinders with a graphene cap (that includes a pentagon) at each end. Graphenes have also attracted the interest of technologists who see them as a way of constructing ballistic transistors. Who else sees some aspect of "protein folding" in this little
excerpt??? Three dimensional shapes, not specified by genetics? Hmmmmm...
methinks there is a relation somewhere in this. But the plot
thickens:
In chemistry, an
aromatic molecule is one in which electrons are
free to cycle around circular arrangements of atoms, which are alternately singly
and doubly bonded to one another.
(More properly, these bonds may be seen as a hybrid of a single bond and a
double bond, each bond in the ring being identical to every other.) This
commonly seen model of aromatic rings was developed by Friedrich
August Kekulé von Stradonitz. The model for benzene consists of two resonant
forms, which corresponds to the double and single bonds switching
positions.
Following this curiosity:
In physics, resonance is an increase in the oscillatory energy absorbed by a system when the frequency of the oscillations matches the system's natural frequency of vibration (its resonant frequency). Examples are the acoustic resonances of musical instruments, the tidal resonance of the Bay of Fundy, orbital resonance as exemplified by some of the Jovian moons, the resonance of the basilar membrane in the biological transduction of auditory input, and resonance in electronic circuits. A resonant object, whether mechanical, acoustic, or electromagnetic, will probably have more than one resonant frequency (especially harmonics of the strongest resonance). It will be easy to vibrate at those frequencies, and more difficult to vibrate at other frequencies. It will "pick out" its resonant frequency from a complex excitation, such as an impulse or a wideband noise excitation. In effect, it is filtering out all frequencies other than its resonance. All of which certainly has information pertaining to complexity,
and to biological systems as well. But I was astonished to see the Bay of Fundy
mentioned. This is a well-known name from having lived in Nova Scotia for so
long.... so I had to follow that link:
Folklore in the Mi'kmaq Nation claims that the tides are caused by a giant whale splashing in the water. Oceanographers attribute it to tidal resonance resulting from a coincidence of timing: the time it takes a large wave to go from the mouth of the bay to the opposite end and back is the same as the time from one high tide to the next. The Bay of Fundy is famously known for its high tides. Several proposals to build tidal harnesses for electrical power generation have been put forward in recent decades. Such proposals have mainly involved building barrages which effectively dam off a smaller arm of the bay and extract power from water flow through them. One such facility exists, a dam and 18 megawatt generating station on the Annapolis River at Annapolis Royal, Nova Scotia, but larger proposals have been held back by a number of factors, including environmental concerns. Damming a large arm of the Bay of Fundy would have significant and not well-understood effects both within the dammed bay itself and in the surrounding regions. Intertidal habitats would be drastically affected and a facility would bring the bay closer to resonance, increasing tidal range over a very large area. One effect could be an increase in tidal range of 0.2 m (from approximately 1 m) for certain coastal sites in Maine, possibly leading to flooding. All in all, a fascinating refresher, and addition, to my basic
education in these and related fields.
Judith
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