James Corrigan
Physics
December 6, 2010
Physics ePortfolio Project
Physics ePortfolio Project
Aristotle began his scientific history in an educational program started by Plato. After the death
of Plato he eventually began his own school where he spent the rest of his life. He there also involved
himself in teaching and researching. Aristotle researched many different topics ranging from physics and
biology to philosophy and politics. “The aim of Aristotle's logical treatises (known collectively as the
Organon) was to develop a universal method of reasoning by means of which it would be possible to
learn everything there is to know about reality.” (Kemerling) “The Categories of Aristotle are
classifications of individual words (as opposed to sentences or propositions), and include the following
ten: substance, quantity, quality, relation, place, time, situation, condition, action, passion.” (Aristotle
(384—322 BCE)) Aristotle apparently tried to organize these categories in the order that one would
normally use to find knowledge about a topic.
Dark matter is a controversial theory that states most matter in our universe is dark matter or
matter than is invisible to us humans. There are a few reasons that lead scientists to believe it is there
such as the motions of astronomical objects and in order to allow gravity to amplify the small
fluctuations in the Cosmic Microwave Background to form large galactic structures. When observing
other galaxies there must be enough mass there for gravity to prevent all other objects from flying
apart. And when measurements are done there simply isn’t enough mass there from what can be seen.
Thus there must be some other form of matter there which is explained through dark matter. (White)
Dark Energy is a force that only recently discovered is forcing the galaxies farther and farther
apart and causing the expansion of the universe to speed up. The scientists now believe that after the
big bang everything was held together by gravity but once the massive objects became too far apart the
repulsive force or “dark energy” took over causing the speed up of space. According to the scientists it
must be that this is the case, either that or Einstein’s theory of gravity is not correct. (NASA)
In the 1920’s it was discovered that galaxies were flying away from our Milky Way galaxy. This
was discovered used what is called Doppler shift measurements. During these measurements it was
concluded that there are many galaxies outside of our own, these galaxies are all receding from us if we
go to large enough distances, and the velocity of recession is proportional to the distance from us. This
information also solves a century old paradox called the Olber’s Paradox. “Briefly, if the Universe is static
and uniformly filled with stars and galaxies, one can show that the night sky should be as bright as the
surface of a star. That this is not so constitutes the paradox. The expansion of the Universe solves this
problem…” (Expansion of the Universe )
Einstein’s theory of special relativity deals with the movement of particles traveling at speeds
close to those of the speed of light. While his theory still holds true to this day it is not as general as the
theory by Newton which deals with more everyday speeds. Einstein’s theory is made up of 2 statements.
“First, the speed of light is the same for all observers, no matter what their relative speeds.
James Corrigan
Physics
December 6, 2010
Physics ePortfolio Project
And second, the laws of physics are the same in any inertial (that is, non-accelerated) frame of
reference. This means that the laws of physics observed by a hypothetical observer traveling with a
relativistic particle must be the same as those observed by an observer who is stationary in the
laboratory.” (SLAC)
Einstein’s general theory of relativity though was quite different. It was his goal to remove the
restrictions that were placed on his special theory of relativity which was the acceleration or force.
Many tests have been done and have proven that all of these theories of Einstein’s have been correct.
“Einstein's theory predicts that the direction of light propagation should be changed in a gravitational
field… The General Theory of Relativity predicts that light coming from a strong gravitational field should
have its wavelength shifted to larger values (a redshift)… The electromagnetic field can have waves in it
that carry energy and that we call light.” To date Einstein’s General Theory of Relativity is the most
accurate theory, though under most circumstances Newton’s three laws are sufficient enough.
(Gravitation and the General Theory of Relativity)
To support his theory of relativity Einstein developed what he called the Principle of
Equivalence, which states: All local, freely falling, non-rotating laboratories are fully equivalent for the
performance of all physical experiments. It has also been stated another way which is: “It is impossible
to tell by experiment whether you are in accelerated frame of reference or in a gravitational field.” “At
any point, we can replace the local effects of gravity by an accelerated frame of reference. However,
different frames of reference are required for different points in space, since the magnitude and
direction of gravity varies between locations.” (Principle of Equivalence)
According to the Stanford Encyclopedia “Quantum mechanics is, at least at first glance and at
least in part, a mathematical machine for predicting the behaviors of microscopic particles — or, at
least, of the measuring instruments we use to explore those behaviors…” Mathematically quantum
mechanics makes sense but the world that it describes is quite controversial. There is very little
agreement as to what quantum mechanics means in the real world. (Ismael)
Erwin Schrödinger is most known for creating a powerful model of the atom in 1926.
“Schrödinger combined the equations for the behavior of waves with the de Broglie equation to
generate a mathematical model for the [atom].” This new model describes the electron as a wave and
tells us where it is most likely to be found. The old model, the Bohr model, was a “one-dimensional
model that used one quantum number to describe the distribution of electrons in the atom.” This model
focused only on the size of the orbit but the new Schrödinger model allowed the electron to be viewed
as taking up three dimensional spaces. “The three coordinates that come from Schrödinger's wave
equations are the principal (n), angular (l), and magnetic (m) quantum numbers. These quantum
numbers describe the size, shape, and orientation in space of the orbitals on an atom.” (Erwin
Schrödinger)
James Corrigan
Physics
December 6, 2010
Physics ePortfolio Project
The Michelson-Morley experiment was first off a test to try and find the exact speed of light.
First they were able to conclude that light really was a wave and from there they were able to find out
the speed at which it was travelling at. After finding the speed they moved on to trying to find more
about the Aether Wind. This wind is a force that pushes the light much like the way moving water would
push someone trying to swim across a river. This force slightly pushes the light off its course, but
because the light is what shows us were objects are we could not know a difference. It would only
appear is if the object was in a different position than it really is. (Fowler)
In the equation 𝐸 = 𝑚𝑐 2 Einstein first realized that matter and energy are really only different
forms of the same thing. Matter can become energy and energy can become matter. Though the only
way for matter to be completely turned into energy is if it met an equal amount of antimatter; a
negatively charged form of matter. Antimatter though obviously is not a very common piece of matter
so nothing is truly changed completely into energy. Another way to turn matter into energy is by means
of nuclear fusion. “Two protons stuck together have less mass than two single separate protons! When
the protons are forced together, this extra mass is released ... as energy! Typically this amounts to about
0.7% of the total mass, converted to an amount of energy predictable using the formula.” (Willis)
Ohm’s laws deals with power (P), voltage (E), current (I), and resistance (R) and defines the
relationships between them. “One ohm is the resistance value through which one volt will maintain a
current of one ampere.” The current is the electricity that flows down the wire or any other conductor
and it is measured in Amperes. The voltage is the difference is electrical potential between two points in
a circuit. It's the push or pressure behind current flow through a circuit, and is measured in (V) volts.”
“Resistance determines how much current will flow through a component. Resistors are used to control
voltage and current levels. A very high resistance allows a small amount of current to flow. A very low
resistance allows a large amount of current to flow. Resistance is measured in ohms. (P) Power is the
amount of current times the voltage level at a given point measured in wattage or watts.” (the 12 Volt)
When dealing with Thermodynamics you must know that energy exists in many forms such as
heat, light, chemical and electrical energy. Thermodynamics is the study of energy. The first law of
thermodynamics states “Energy can be changed from one form to another, but it cannot be created or
destroyed. The total amount of energy and matter in the Universe remains constant, merely changing
from one form to another.” The second law of thermodynamics states "in all energy exchanges, if no
energy enters or leaves the system, the potential energy of the state will always be less than that of the
initial state." In energy there are two different types Potential and Kinetic. Potential is energy that is
stored and has not yet been used. Kinetic energy is energy that is in use or is in motion. (Farabee)
“Absolute zero is the theoretical temperature at which entropy would reach its minimum value.
The laws of thermodynamics state that absolute zero cannot be reached because this would require a
thermodynamics system to be fully removed from the rest of the universe.” (AbsoluteAstronomy)
“Absolute zero is the point at which the fundamental particles of nature have minimal vibrational
motion, retaining only quantum mechanical, zero-point energy-induced particle motion. By international
James Corrigan
Physics
December 6, 2010
Physics ePortfolio Project
agreement, absolute zero is defined as precisely; 0 K on the Kelvin scale, which is a thermodynamic
(absolute) temperature scale; and –273.15 degrees Celsius on the Celsius scale.” (ScienceDaily LLC)
Boyles law explains the relationship between the pressure and volume of confined gas held at a
constant temperature.” The product and volume is exactly a constant for an ideal gas.”
𝑃𝑉 = 𝑘 (Benson)
James Corrigan
Physics
December 6, 2010
Physics ePortfolio Project
Works Cited
Aristotle (384—322 BCE). n.d. <http://www.iep.utm.edu/aristotl/>.
Erwin Schrödinger. n.d. <http://chemed.chem.purdue.edu/genchem/history/schrodinger.html>.
Expansion of the Universe . n.d. <http://csep10.phys.utk.edu/astr162/lect/cosmology/expansion.html>.
Fowler, Michael. The Michelson-Morley Experiment. n.d.
<http://galileoandeinstein.physics.virginia.edu/lectures/michelson.html>.
Gravitation and the General Theory of Relativity. n.d.
<http://csep10.phys.utk.edu/astr162/lect/cosmology/gravity.html>.
Hubble Site. n.d. <http://hubblesite.org/hubble_discoveries/dark_energy/>.
Ismael, Jenann. Quantum Mechanics. n.d. <http://plato.stanford.edu/entries/qm/#VecVecSpa>.
Kemerling, Garth. Aristotle . n.d. <http://www.philosophypages.com/ph/aris.htm>.
NASA. Dark Energy, Dark Matter. n.d. <http://science.nasa.gov/astrophysics/focus-areas/what-is-darkenergy/>.
Principle of Equivalence. n.d. <http://www.marts100.com/equivalence.htm>.
SLAC. Special Relativity. n.d. <http://www2.slac.stanford.edu/vvc/theory/relativity.html>.
White, Martin. Dark Matter. n.d. <http://astro.berkeley.edu/~mwhite/darkmatter/dm.html>.
James Corrigan
Physics
December 6, 2010
Physics ePortfolio Project