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发帖数: 9094 | 1 School homework for a 7th grader: An Essay about Scientific Research and Its
Impact
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Pave the Way for the Future
A few years ago while watching a documentary by Al Gore, I first heard of
global warming. We were living in San Diego, CA at the time. As you can
imagine, the idea of Southern California disappearing due to a rising sea
level was absolutely horrible to me. Global warming has started popping up
in the news more and more often since then. The culprit might be the
consumption of fossil fuels coupled with the generation of greenhouse gases
such as carbon dioxide. People claimed that we had already burnt through
half of the easily-found resources for fossil fuels, and that we would run
out completely in the next 25-50 years. I also learned that because of this,
scientists were looking into alternative energy sources to replace oil and
coal. One particular method caught my eye: atomic fusion.
Atomic fusion is a type of nuclear reaction that combines two atoms into one
. Because it is a highly clean method of energy output, scientists and the
government of many countries consider fusion as the energy for the future.
Unlike fossil fuels such as coal and oil, fusion reactions do not create
carbon dioxide and therefore will not contribute to the greenhouse effect
and global warming. The fusion reactions use raw materials of deuterium and
lithium, the latter of which is used to create tritium. Both elements can be
extracted from seawater and there is enough supply to last more than
millions of years.
Attracted by the beauty of this clean energy source, scientists have been
working on atomic fusion in the past 50 years to make it happen. But there
have been many challenges. According to the Lawson criterion, a fusion
reactor must hold the deuterium/tritium mixture at extremely high
temperatures (over 150 million degrees Celsius), pressure and density for
the fusion to become self-sustainable and produce positive net energy. This
condition is necessary to overcome the repelling electromagnetic forces
exerted by the two positive nuclei and to bring the atoms close enough for
the strong force to over-take and bind the atoms together. Creating such a
condition not only makes the fusion reaction immensely expensive and hugely
difficult to achieve but also impractical. The biggest problem with fusion
reaction today is that it requires more energy input than the energy output
produced. Also, if the radioactive tritium escapes the reactor or isn’t
handled safely, it is very dangerous. Since tritium is able to dissolve in
water and can cause cancer in higher doses, workers at the plant could (in
the worst-case scenario) die every 18 years from radiation exposure.
One of the great virtues that humans possess is persistence. Though faced
with the obstacles, we do not give up. Currently an International
Thermonuclear Experimental Reactor (ITER) is under construction in southern
France. As a worldwide collaboration, ITER aims to prove that fusion is a
legitimate source of energy, and intends to produce at least 10 times the
amount of energy it consumes. The machine it will use is named the Tokamak,
and is the same type of machine that JET used in the first attempt of fusion
. The Tokamak is a donut-shaped machine that uses a magnetic field created
by superconducting coils and a running current to trap the plasma reactants
away from the walls of the machine. So far, the Tokamak is one of the best
options for efficient atomic fusion.
Nuclear fusion is not the only energy production method that scientists are
researching. Solar energy, wind energy, hydroelectric power, and geothermal
energy are all plausible methods and components of the renewable energy
sources for the future. There are many discussions about how energies will
be created in the future. I found the discussions not only interesting in
terms of the basic science involved, but also inspiring since it would
impact the future of both the Earth and the humanity.
Of course, like fusion, the other energy sources have their own drawbacks.
For example, solar and wind energy are extremely variable to change, as they
depend on the weather. Therefore, they are rather unreliable sources of
energy. Hydroelectric power, though more stable, can negatively affect its
surrounding habitats and is dependent on precipitation. Geothermal energy
seems reliable, but can actually be inconsistent and may cause tremors near
the drilling locations. In sum, none of the other energy sources is a better
, sustainable alternative to atomic fusion.
There are many kinks that need to be sorted out before we can replace the
fossil fuel with reusable sources. However, the era of recyclable energy is
coming. Although at the present stage, the high temperature and pressure
required make the atomic fusion extremely unprofitable, perhaps to such
extents as losing money for the process, atomic fusion is still one of the
more likely options, based on its relatively clean method of production, and
its easily-procured reactants. Just as the control of fire became the
turning point in human evolution, I believe that innovations to safely
summon the power of atom fusion would usher in a new era for human
civilization and extraordinary discoveries in science would make it a
reality! |
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