Intro
I’m going to take you on a little tour, a depiction of the lifecycle of a carbon atom.
And by lifecycle, I am not implying that this little guy has a half life. It literally is
possible for this atom to go through several totally different phases and end up
exactly where it started off.
Although the ramifications of what is happening to this atom as it is grouped into
various types of organic molecules are fascinating, that is a story for the chemists
and biochemists. I would like to focus on the physical large-scale forces undergone
by this atom. The use of “large scale” is deliberate – while a full description of the
nuclear and electrostatic forces that influence this atom would be interesting, it is
beyond the scope of what I would like to present. Therefore, I will be concentrating
on the group of physical properties and phenomena that can be observed to act on
the materials of which this atom is a part.
Enjoy!
Page 1 – C falling onto head of a monkey
Let us go back to the age of dinosaurs, and pick a random carbon atom. The intent is
to follow it from here down to the present day, so let’s pick an honest one. We don’t
have room for an atom that shirks its duties and capabilities, we want a versatile,
hard-working genius.
Ah, let us pick an apple. It’s loaded with organic molecules. Let’s pick one, and
select two carbon atoms in the chain. And why not give them names? They will be
our friends for a substantial period of time. For simplicity, I will go with Jack and Jill.
The apple in which Jack and Jill currently reside is hanging from a low branch of an
apple tree. It is in equilibrium, since the force of its mass acted upon by
gravitational acceleration (F = ma) is being counteracted by the normal force being
exerted upon it by the tree branch via the stem of the apple.
But, my friends, this is what is known as unstable equilibrium. The apple is quite
ripe, hence the stem’s ability to transmit forces is quite weak. Given one large
enough external force to act on the system, the stem will snap and the apple and
branch will be free to react separately to the forces acting upon them.
Enter a gust of wind of constant velocity. It exerts a force on the tree branch (the
mass of the air coming into contact with the branch, times the acceleration of the
branch as it goes from zero motion to an altered position due to the wind pressure).
This is slightly too much for Jack and Jill’s apple to remain aloft. In a split second,
the horizontal force applied to the stem snaps it, and the apple is suddenly free to
act alone under the force of gravity.
Who should be sitting underneath the tree but a small plant eating dinosaur,
appropriately of the genus isaacus newtonosaurus. The dinosaur experiences a
sudden force exerted by the apple (accelerating downward at 9.81 meters per
second per second) as it hits its skull and the apple comes to a stop.
At this juncture, the dinosaur (quite unaware of the physics that brought about this
free serving of food) proceeds to eat the apple and go about his business.
Jack and Jill are processed by the dinosaur’s digestive system into an ATP cell inside
the its muscular system.
Page 2 - C gets enmeshed in an oil seam when monkey decays
Shortly following the events described above, the dinosaur dies (of natural causes)
and begins to experience decay. A sequence of natural disasters follows, turning the
entire area under and burying it deep beneath many layers of strata over a period of
time.
During this time, Jack and Jill undergo a series of crushing forces from the weight of
the overburden, and are transformed by heat and pressure into different types of
molecules.
The physics acting on Jack and Jill involve linear and rotational forces as they are
washed into the depths of the earth. These forces result from the actions of gravity,
moving air and water, and movement of the land.
The organic material of which Jack and Jill are part is transformed over time into a
subsurface oil pool.
Page 3 - C is raised to the surface when an oil rig penetrates seam, and is refined
into gasoline
Let’s fast-forward to modern times. A wildcat well has penetrated the oil field and
resulted in the drilling of more wells. Instead of getting into the details of oil
movement across an oil field, we will over-simplify the situation and observe the
handful of crude oil containing Jack and Jill as it moves up the well casing.
The oil has been under considerable pressure, as a result of the mass of the ground
above it acting downward under the influence of gravity. When the integrity of the
ground layer was intact, there was no outlet for this fluid pressure, and the entire
field is in a state of stable equilibrium. However, once the ground is penetrated,
there is an outlet and the equilibrium becomes unstable. The downward force of the
ground is translated (through fluid mechanics, based on the virtual
incompressibility of fluids) into an upward force on the small area of crude oil that
is free to move upward. The correlation of the downward pressure on the oil field
and the upward pressure of the swiftly rising crude is not perfect, as a result of the
internal fluid forces, viscosity, and our ever-present friend the coefficient of friction.
However, the enormous amount of pressure still causes the oil to rise (against the
force of gravity) quite efficiently, as any oil rig worker will attest.
Jack and Jill are catapulted upward through the well and into a waiting tank. This
crude has been tested and is now being stored for shipment to the refinery.
They eventually reach the infamous cracking column at a Louisiana refinery, and
through the cracking process are transformed into a molecule of gasoline. The
gasoline is pumped into a storage yard, through forces applied by a pump that
creates a linear fluid motion to direct fluid through a given route (a pipeline).
Page 4 – C is burned in a car engine and becomes exhaust (CO2)
Following this series of events, the gasoline of which Jack and Jill are part is pumped
into a tanker truck and transported to Alaska, in one of the ironies of the oil
industry.
During this time, Jack and Jill undergo a position change of several thousand
kilometers, and this change is accompanied by periods of positive and negative
acceleration, and constant and non-constant velocity, as they are moved north, acted
upon by the (usually forward) motion of the truck, and as always by gravitational
acceleration. Fluid turbulence also acts on the gasoline, despite the baffles built
into the tanks, but this is a far more complex issue than we can deal with here, other
than to say that it is caused by the acceleration of the truck (not only forward, but
around curves and over bumps in the road).
Eventually Jack and Jill, with billions of atoms similar to them in similar molecules,
are deposited in an underground tank at a gas station. Before very long, they are
pumped up into the gas tank of a car, for final consumption.
Jack and Jill, while involved in the general motion of the car as it moves, eventually
experience a forward acceleration from the tank into the engine when the car’s fuel
pump engages them. Soon they are vaporized and sprayed into the engine, where
the molecules of which they are part combust and release energy into the car’s
engine. This combustion creates an increase in pressure as the potential energy
bound up the molecules’ chemical bonds is transformed into kinetic energy which
forces the piston’s downward. The energy first imparted to the molecules as
pressure in the oil field, which was stored up in the chemical bonds, is now released
to do work, as it is translated through the fluid actions in the car’s transmission into
the wheels of the car.
The gasoline is broken down after combustion into very simple molecules. Jack and
Jill become separate molecules of carbon dioxide, and are expelled into the
atmosphere by the car’s exhaust system.
Page 5 – C is absorbed by an apple tree and becomes another apple.
There are a number of various outcomes for the carbon dioxide molecules released
into the air, but those of which Jack and Jill are part are (luckily) absorbed into
plants. The actions of wind separate the two, and Jack is absorbed into the
chlorophyll of an apple tree in a greenhouse in Fairbanks (demonstrating the
complete lifecycle of the carbon atom), while Jill is absorbed into a birch tree and
becomes part of the organic material of the tree’s leaves.
It happens to be the summertime. As the seasons move on, the birch leaves begin
detaching from the branches and become susceptible to the actions of wind. A
particularly hard gust of wind hits a tree on the University campus, and the leaves
are blown along the air (accelerated along with the air mass). The fascination of this
phenomenon is not lost on a certain Dr. David Newman, as they swirl past his head
when he walks into the Reichardt Building.
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