pwn physics 365: physics history, vocabulary, and resources every day of the year

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On this day in physics: 09 March 1611- Johannas Fabricius, a Dutch astronomer, was the first to observe and formally publish a paper on sunspots, dark spots on the Sun which he found quite curious. 

Word of the Day- Positron- The positron is the antiparticle of the electron. It was first hypothesized by PAM Dirac and discovered in 1932. It has the same mass and spin as an electron, but  has opposite charge. If an electron and positron were to collide, they will annihilate creating gamma ray radiation and the two particles will vanish.

Quote of the Day: "In the beginning there was nothing, which exploded." -Terry Pratchet

Keywords: Positron, electron, charge, annihilation, antiparticle.

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On this day in physics: 08 March 1871 - James Clark Maxwell was the first apointee of the Cavendish Professor of Physics at Cambridge. At the time Maxwell was a relatively unknown physicist, and had yet to do his best work regarding electromagnetism. 

Word of the Day- Maxwell Equations- There are four Maxwell Equations which led him to be the heavyweight in physics that he is. These four equations deal with the nature of electromagnetic waves, which we also know define how light behaves, because light is an electromagnetic wave. In my senior level electromagnetics II course in college (oh by the way they don't even introduce maxwell equations until electromagnetics TWO.), these are pretty much all you need. They do everything to describe light. So, the four laws are as follows: Gauss's Law, Gauss's Magnetism Law, Ampere's Law, and Faraday's Law. Now, from the sounds of it, he just compiled together from three other guys some laws and made them his own. Kind of yes and kind of no. What he did was consolidate known electromagnetic behaviour in such a way that definitively showed that electricity and magnetism are intertwined in a way that cannot be separated. They induce each other. The other monster thing that he did was this little nugget of information that the speed limit for the propagation of an electromagnetic wave is the same as the speed of light, AND THAT LIGHT IS IN FACT AN ELECTROMAGNETIC WAVE. That is a big deal. 

I think we'll dig into each equation on its own for exclusive words of the day, because there is way too much to do in just a single episode. Maybe the next time we have a lapse, we'll do a monster Maxwell Equations episode to bring us right up to speed. 

Quote of the Day: "[Maxwell's Work] is the most profound and the most fruitful that physics has experienced since Newton" - Albert Einstein 

Keywords: Maxwell, Equations, Electromagnetics, Waves, Light, Flux

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On this day in physics: 01 March 1966 – first spacecraft crash-lands on Venus, 02 March 1972, the spacecraft Pioneer II was launched which made close passes near Jupiter and Neptune before saying good bye to our lovely solar system. It is now SIX BILLION miles away from us. 03 March 1847, we say Happy Birthday to Alexander Graham Bell, the inventor of the telephone! It is also the birthday of Georg Cantor, the founder of modern set theory, and the first person to define different levels of infinity, the first two being countably infinite and uncountably infinite. Without much surprise, mathematics this intense did wind up driving him insane, and his work was repeatably marred with bouts of insanity. 04 March 1976, we salute the passing of Walter Schottky, the man for whom the Schottky effect is named. The Schottky effect (maybe more on this one day). 05 March 1616- The theory set forth by Copernicus that the Earth orbits the Sun is declared to be false doctrine by Bishop of Albano. 06 March 1913- Niels Bohr wrote the first of three papers regarding his theory of atomic structure. 07 March 1979- Photos from the Voyager spacecraft were analyzed and the ring around Jupiter was discovered. By contrast, the rings of Saturn had been known since 1610. 

Word of the Day- The base units are very important. Think of the unit of force, the Newton. The Newton can be simplified to be kilogram per meter per second squared. So, many units like this are called "derived units". There is a limit to this. In 1875, the Systemme Internacionale met in france and agreed that for the world, there are 7 base units, and went on to determine a standard for each of these. Now most of these units are for human-sized sales, since we are human beings and those tend to be the sizes of items we work with. However, the thing to walk away from in this is that there are really only 7 items which are unique in terms of weights and measures, from which everything else can be explained. So, for this 7 day lapse, I offer you the 7 base units. 

The first of these fundamental measurable quantities is of course length. Length determines the distance between objects, or the distance of an object. As we've learned from relativity, this measurement can vary depending on your speed, however in our world we can assume that that speed is roughly constant. The standard unit of length is the meter.

The second measurable quantity, and probably the one most people measure the most is mass. The standard unit of mass is the kilogram, the ONLY standard unit which uses a power of ten prefix (kilo). A kilogram is defined to be the weight of one litre of water, and a litre is of course one thousandth of a cubic meter, the meter being our aforementioned first base unit.

The third measurable quantity is time. We all know what time is, or at least we think we do. It's a very bizarre feature of our universe, and there is nothing which behaves quite like it. It's the only dimension which seems to only move in one direction, constantly pressing us forwards. It puts the order to all the events in our lives, and allows us to traverse space incrementally, as time moves on. The base unit is a second, which is currently defined to be *roughly* nine billion oscillations of light emitted from a Cesium Atom. 

The fourth measurable quantity is electric current. As electrons move, they generate a magnetic field, and also an electric field. The motion of electrons is what produces current. Current also produces voltage, and the two are directly relatable with the resistance of the conductor being the multiplier between them. The base unit of electric current is the Ampere. 

The fifth measurable quantity is temperature. We check the temperature all the time. Temperature is the amount of energy an object or space contains. Depending on where you are in the world, you probably use Fahrenheit or Celsius, but for calculations, we use the Kelvin. It uses the same gradation as the Celsius scale, i.e. 1K = 1 degree Celsius, but the difference is that 0K is what is known as ABSOLUTE ZERO, absolutely no energy. 0 Celsius is the freezing point of water. 

The sixth measurable quantity is the amount of a substance. Not to be confused with mass, this is the count of how many particles there are. The base unit of amount is the mol, or 6.022e23 atoms. One mol of gold, would be much heavier, or have much more mass than one mole of hydrogen, which is significantly lighter. How much there is is a fundamentally measurable quantity.  

The seventh and final measurable quantity: luminous intensity, think of the sun shining on your face at high noon versus at sunset. The light intensity is less, and it's possible to think about it as the amount of photons per unit area, the unit of which is candela. The standard candle emits roughly 1 candela of luminous intensity. Candela actually means candle in latin.

So there you go guys, seven words of the day in a single episode. Length, Mass, Time, Current, Temperature, Amount of Substance, and Luminous Intensity. Allegedly, from this, the rest will flow. 

Quote of the Day: “How wonderful that we have met with a paradox. Now we have some hope of making progress.”-Niels Bohr

Keywords: Base Units, Meter, Length, Mass, Kilogram, Time, Second, Current, Ampere, Luminous Intensity, Candela, Amount, Mol, Mole, Temperature, Celsius, Kelvin

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On this day in physics: 28 February 1928- Chandrasekhara Venkata Raman, an Indian Physicist, commenced experiments with light interference which led to his discovery of what is now known as the Raman Effect. Because of this it is also the date of National Science Day in India.

Word of the Day- Raman Effect is something that occurs during some photon scattering. If you shine light through a gas, it is possible to imagine it like a single photon traveling through a sea of pool balls. Each time the photon collides with one of the pool balls, (the pool balls being gas particles) the photon merely bounces off, and may change direction, but that's that. The atom is not changed, and neither is the photon. But sometimes, usually 1 in 10 million interactions, the photon is absorbed and moves one of the electrons into a higher-than-usual energy state, creating an excited electron, and changing the fundamental nature of the particle. This is known as the Raman effect. 

Quote of the Day: "The true wealth of a nation consists not in the stored- up gold but in the intellectual and physical strength of its people." -C.V. Raman

Keywords: Electron, Scattering, Energy, Feynman, Diagram, Virtual. Photon, Raman

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On this day in physics: 27 February 1961- UNIVAC Solid State 90, the world's first mobile computer was loaded into a van.

Word of the Day- Electron Shells- As electrons orbit an atom, they do not simply swarm in a sphere equidistant from the nucleus. As it turns out, there are different radii which the electrons tend to form in depending on how many electrons there are surrounding the nucleus. The first shell has two electrons, then the next has 6, the next has 10, then 14, then 18. Each of the atoms on the periodic table has one more electron and proton than the last, and they fill each of the shells in order.

Quote of the Day: "Don't tell me the sky is the limit when there are footprints on the Moon." - Anonymous

Keywords:  Electron, Shells, UNIVAC, Computer

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On this day in physics: 04 February 2016- We salute the passing of Edgar Mitchell, the sixth man to walk on the moon, on the Apollo 14 mission. Again, we solute you, and we'll see you again in the quote of the day. 

Word of the Day- Parabola- The shape formed as the graphical solution to a quadratic equation, or an equation whose highest order or exponent is x^2. It is also the shape traced out by an object which you throw in the air, say a baseball or a basketball. It is possible to perfectly model projectile motion with a parabola. 

Quote of the Day: “From out there on the moon international politics look so petty. You want to grab a politician by the scruf of the neck and drag him a quarter of a million miles out and say 'Look at that you son of a bitch.'”

-Edgar Mitchell, Apollo 14

Keywords:  Parabola, Quadratic, Kinematics, Gravity, Acceleration, Motion, Apollo 14, Edgar Mitchell

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On this day in physics: 25 February 1837- Thomas Davenport patented the electrical motor. 

Word of the Day- Tangent- A tangent is a line which touches a curve at one and only one point. There is a special definition of tangent in calculus, however. The derivative is the slope of the line tangent to the curve at that point. So, I personally have had a very difficult time envisioning this in my mind. If I think of a curve, such as a sine, cosine, parabola, etc. I feel like there are many lines which can touch the curve at one specific point and satisfy this definition. So, we will defer to the man who independently invented calculus alongside Issac Newton, Gottfried Leibniz. He says that the tangent line is the line which passes through two points on a curve which are "infinitely close" together. That to me makes much more sense. Take two points on the curve, and envision the line which goes through this, then bring those points closer and closer together, towards the point you desire, and the line that it approaches is your tangent line. Because of their usefulness in derivatives, tangent lines are very important in almost every aspect of physics.  

Quote of the Day: "Prediction is very difficult, especially when it's about the future" -Niels Bohr 

Keywords:  Tangent, Line, Derivative, Calculus, Curve.

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On this day in physics: Cruising wikipedia I came across the following excerpt: "Higgs was presented with an engraved loving cup by the Rt Hon George Grubb, Lord Provost of Edinburgh, in a ceremony held at the City Chambers on Friday 24 February 2012. The event also marked the unveiling of his handprints in the City Chambers quadrangle, where they had been engraved in Caithness stone alongside those of previous Edinburgh Award recipients."

Word of the Day- Googol, it is a huge number. A googol is a 1 followed by 100 zeros. It is 10 to the 100th power. "Other names for googol include ten duotrigintillion on the short scale, ten thousand sexdecillion on the long scale." Likewise, a googolplex, is 10 to the googol power, or 10 followed by a googol's worth of zeroes. 

Quote of the Day: "An expert is someone who knows some of the worst mistakes that can be made in his subject, and how to avoid them." -Werner Heisenberg

Keywords: Googol, Googolplex, Math, Mathematics, Heisenberg.

Dig deeper at pwnphysics.blogspot.comOn this day in physics: 23 February 1927, Werner Heisenberg writes a letter to his colleague Wolfgang Pauli, describing his infamous Heisenberg Uncertainty Principle.Word of the day- Heisenberg Uncertainty Principle- A big dog. One of the biggest principles in quantum mechanics. So, as scientists, especially scientists who have done any type of real lab work, think that we have a really good handle on the ability to measure things. And, even if our scale is only good to a tenth of a pound, it is possible to build something good enough to measure down to the exact amount of weight? Right? Wrong. There are limits to what we can measure, and that's evident from the Heisenberg Uncertainty Principle. What this principle says is that at the most microscopic measurements, the uncertainty of the position multiplied by the uncertainty of momentum must be greater to or equal to a constant which we call h-bar divided by 2 (5.272859 × 10-35 m2*kg/s). Now, this might seem like a crazily small number, and for human scales, it's totally not affecting our life at all, but at the quantum scale, there is a limit to your ability to measure. So, on any measurement that you take, there is going to be some amount of uncertainty, example, your bathroom scale is probably good to about one hundredth of a pound, which means, plus or minus .01 lbs, the measurement is reliable. This is called the "uncertainty" of the measurement. What this means at quantum scales? The more precise you know the position, the less precise you'll know the momentum, and if you choose to have a high level of precision on the momentum, the higher the uncertainty of the position. And there is no way to "burn the candle at both ends" here. You cannot know the momentum and position of something with exact certainty. Sorry friends. There is a great joke about this: Heisenberg is driving his car down the road, and he gets pulled over by a police officer for speeding. The officer walks to Heisenberg's car, and asks him "Do you know how fast you were going?", and Heisenberg says 'No, but I know exactly where I am!'. Get it? Because..you know..uncertainty....anyways....Quote of the Day: "What we observe is not nature itself, but nature exposed to our method of questioning." -Werner HeisenbergKeywords: Heisenberg, Uncertainty, Principle, Position, Velocity, Momentum, h-bar.

Dig deeper at pwnphysics.blogspot.comOn this day in physics: 22 February 1857- Happy Birthday to Heinrich Hertz who would have turned 159 today. He was a physicist who first proved the existence of electromagnetic waves. He is also the namesake for our unit of frequency, the Hertz. Word of the day- Ion- An ion is an atom which has fewer electrons than protons, or more electrons than protons. We like to think of most atoms in their "steady state" as having an equal number of electrons orbiting the nucleus of protons and neutrons. Because there are an equal number, the amount of positive and negative charges cancels out, leaving a net charge of 0. However, this is not always the case. There are negative ions and positive ions, which can be highly attractive to electrons or other atoms, in an effort to create a situation where the net charge is zero. Example: Sodium Chloride, or NaCl. Sodium, or Natrium (hence the Na), is an atom which can come in the flavor of a positive ion, with one fewer total electron count than proton count, giving a net charge of +1. Cholrine can come in the flavor of having one extra electron, giving a net charge of -1. These two ions will "stick together" and together, they will have a net charge of 0, a very steady molecule. Many of these molecules will form what's known as a lattice structure, with each particle changing between sodium and chlorine in the lattice, giving a net charge of 0 across the entire structure. This is what is in your salt shaker. Quote of the Day: "All of physics is either impossible or trivial. It is impossible until you understand it, and then it becomes trivial." -Ernest Rutherford Keywords: Ion, Electrical, Charge, Sodium, Chloride, Salt