Here's a paper I just finished. The topic is SOOOO vague, "What is Physics?" I had a tough time deciding on what to write. It doesn't flow that greatly (well, it does from one paragraph to the next...a little...). There's not much of a point, except to say that there's a lot to physics. The only guideline was 4 pages. Things I'm graded on: main ideas are supported by detail; quality details beyond the obvious; accuracy of facts; sources (bibliography); no significant grammar/spelling error that distupts the content; personality. I mean, even if it doesn't flow that well, I'll do good. Well, here it is (and note that it was written in less than 2 days):
The Many Faces of Physics
Physics is the study of nature. Physics deals with everything from how planets revolve around stars, to how electrons revolve around nuclei. There are many faces to physics, including mechanics, electromagnetism, the quantum mechanics of chemistry, and electrical sciences. Mechanics is the study of physics on the large scale, how objects move and interact. Electromagnetism is the discipline of photon radiation, light, electricity, and magnetism. Quantum mechanics of chemistry is the behavior of atomic particles, chemical phenomena, and particle interaction. Electrical science is comprised of computers, circuitry, and appliances.
Mechanical physics is the basis of physics. In the 1680s, Sir Isaac Newton discovered that things fall down. From this, he devised his three laws of motion. An object with a constant velocity stays at that velocity unless an external force is applied, force equals the mass of the object times the acceleration, and for every action, there is an equal and opposite reaction.
From Newton’s early observations, physics today has the basic motion equations: V = d/t , a = Δv/t , and f = ma. All motion equations are derived from these simple rules; they are used to describe the world on the macro level. Professions like civil engineering use motion and force maxims to solve problems, like preventing a building from collapsing in an earthquake. Mechanics is used to predict the motion of an object, and can be used to make life easier, like simple machines. The laws of mechanical physics makes it possible to lift something very heavy, with a fraction of the effort. Heat is also related to mechanics (Q = mcΔt), which is generated from the motion of particles. On the particle level, physics changes.
Quantum mechanics of chemistry is the physics of particles. Newton’s laws of motion do not apply to particles, primarily because of Heisenberg’s uncertainty principle. The uncertainty principle states that one cannot determine both the position (x) and the momentum (p) of a particle. There is a constant though, Δx • Δp ≥ h/2π, where h represents Planck’s constant, which is 6.626 x 10-34 J • s. One cannot perfectly precisely measure either the position or momentum because it would disturb the system; to determine if a particle is in a position, one would have to touch it, displacing it, and never giving a precise answer. The philosophy that no circumstance can be exactly predicted is another limitation on quantum mechanics; in trying to predict where a particle will be at a certain time, there are only possibilities, some more probable than others, but it is impossible to exactly predict (there is even an extremely small, but definite, chance that the particle will appear across the universe). This and the uncertainty principle may be obsolete in the future, when technology allows the measuring of particles’ location and momentum. Just because modern science can’t predict particle motion and reactions, doesn’t make it a definite law of nature. Superposition is the concept of a particle existing in multiple positions. Once technology can see a particle without disturbing it, accurate predictions about position, momentum, and reaction can be made.
A pioneer of quantum mechanics of chemistry was Erwin Schrödinger in 1935. Schrödinger formulated the quantum numbers. N depicts the energy level (distance) from the nucleus to the electron. L is the number of sublevel divisions in that energy level (l = N – 1). M is the sublevel that the electron is in and its direction (m = 0 and all ± l). Sp is the spin direction of the electron, + ½ is clockwise and - ½ is counterclockwise.
Another branch of quantum mechanics is the different types of particles, mainly in the nucleus. All particles involved in the strong nuclear force between neutrons and protons are called baryons, which include the lambda particle (Λ°), and three sigma particles (Σ ˉ, Σ °, Σ +); all of which have greater masses than protons or neutrons. Mesons are particles that are also implicated in strong nuclear force. The primary meson is the pion (π°, π + [antiparticle π ˉ ]), which keeps protons and neutrons together. The kaon (K-meson) is another important particle. Other mesons include the eta meson (η°), rho meson (ρ+), phi meson (ф), the D meson, the J/Psi meson (J/ψ), which is a special charm-anticharm quark particle, the B meson, and the upsilon meson (Y). Most of these particles’ meanings are not known yet, and many of them include new quarks that provide evidence for even more particles. Particles that do not interfere with the nucleus are called leptons. The most common example is the electron. An interesting lepton is the muon (μ), which has a mass 206x heavier than an electron, yet its behavior is identical to the electron. The neutrino is a neutral lepton with zero mass. The tau particle has a mass 3490x that of an electron, and 17x heavier than a muon; it decays quickly so not much is known about it. The theoretic graviton would be a zero mass particle. The most common zero mass particle is the photon, which is always traveling at about 3 hundred million meters per second. The photon is referred sometimes as a wave instead of a particle. Science today knows a good deal about the photon, which coincides with the next subject of physics.
Electromagnetism is the study of fields and waves. Electric fields act like water or air, where vibrating particles case “waves” of radiation. One of the biggest debates in physics is whether radiation is a wave or particle. In 1928, Neils Bohr offered the complementary principle, stating that both theories are equally valid, and that the decision on which to use should be made accordingly to the situation of the problem. The wave theory describes how light radiates from a source, acting very similar to sound. The particle theory describes how it is a “lump” of energy. Wavelengths (λ) measured in nanometers, can be described as either the distance between the wave crests, or the distance between photons. Visible light ranges from about 780nm to 350nm. Frequency is also used, measured in megahertz (1MHz = 1,000,000 oscillations per second [hz]). At 100Mhz, is FM radio (note radio stations are measured in Mhz, ranging from about 85Mhz to 105Mhz). From 5 x 1014 – 1015 hertz is visible light; above that are X-rays, and above that are harmful gamma rays (γ), which is the waste product of nuclear radioactive decay. Technology has yet to yield an answer to what the zero mass photon is really consisted of.
Another partition of physics is the electrical/computer sciences. This field is a manmade science, because it is not the study of nature, like the other fields mentioned, but a field where nature is used to advance technology. The science in making processors is very complicated; it is constantly searching for better chemical reactions to allow for smaller wire levels and connector points to pack in more levels and more wires, while trying to keep the circuitry’s temperature steady, and making a perfect efficient manufacturing process (the number of rejects vastly out numbers the quantity of successful processors). Data storage is a growing domain, making magnetic storage cards that require no electricity to keep its data, while holding about 180x more information than a diskette, and being an infinitesimal fraction of the size. Liquid crystal display is the hot topic in chemistry today, sending electricity through certain chemicals to emit different colors of light. Computer and electrical sciences involve the laws of electricity in circuitry involving resistors, transformers, transistors, capacitors, etc., and data interpretation and storage. Computers is one of the main steps in science, from the pre-computer era, it was studying how nature works, to now, applying nature for personal use and advancing technology.
The subject of physics ranges from nuclear reactors, to building support bridges, to creating the world’s most powerful laser; The Omega-60 laser at the University of Rochester can implode a pellet with nuclear fusion in 1 billionth of a second with the power 200x that of the energy generated in the US. Only fifty years ago, mankind discovered DNA, and now people have been cloned; technology and discovery is just beginning. As Richard P. Feynman said, mankind is still watching the game of nature, yet is still far from playing it.
