12 January 2015- Dark Matter | PWN Physics 365

On this day in physics: On 12 January 1968 scientists conducted what they called a "controlled excursion", burning up a nuclear rocket in Nevada. It produced a radioactive cloud over Los Angeles. Not everything that's history worthy is great. This should definitely be a reminder that as scientists we should act as responsibly as possible and always consider every possible consequence to our experiments and actions.

Word of the Day: It was too tempting not to cover Dark Matter after covering matter yesterday. It's kind of an interesting word of the day since noone knows exactly what it is. Remember yesterday how I told you how almost everything is made up of matter? Well, it wasn't really true. Roughly 5% of our universe is made of matter. Another 25% is made up of what we refer to as Dark Matter. As we understand the motion of planets and galaxies, based on the mass that we can calculate from what we see, their motion behaves as if they are much more massive, or as if more mass exists somewhere close, but does not emit light in any way that we can detect. That's how it got its name dark matter.

A couple of weeks ago, China launched a probe whose entire purpose is to go on a search for dark matter. Read more about it here.

Killer Resource: Space Shuttle Launch From an Airplane- If this doesn't get you pumped up I don't know what will. Also, if that's not enough, check out these pictures of a shuttle launch from a high-altitude research aircraft here.

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Keywords: Dark Matter, Radioactive Cloud, Dark Energy, Matter, China, Space Shuttle

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11 January 2015- Matter | PWN Physics 365

On this day in physics: On 11 January 1787 William Herschel, discovered the first two moons of Uranus, Titania and Oberon, roughly six years after he discovered the planet itself. The names were given 65 years later by Herschel's son.

Word of the Day: Matter is the stuff around you. It is anything that has takes up space and has mass. This definition is designed to exclude energy such as light, or the motion of particles, such as sound. The majority of matter is made up of atoms, which are made of protons, neutrons, and electrons. Protons and neutrons are then of course made up of up and down quarks.

There are four states of matter. The state with the lowest energy is a solid. Next is liquid. Next is gas. Finally, the least commonly known state of matter is a plasma. Matter behaves distinctly different in each state.

Killer Resource: Wolfram Online Integrator.

If you need to do a quick integral (you know, like you do...) look no further. It does algebraic integrals for you in the snap of a finger. The wonder of Mathematica for your online pleasure.

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Keywords: Matter, Wolfram, Online, Integrator, Mathematica, Uranus, William, Herschel

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10 January 2016- Speed | PWN Physics 365

On this day in physics: 10 January 1936 Birth of Robert Woodrow Wilson, one of the discoverers of the cosmic microwave background radiation along with Arno Penzias (Source).

Speed is...wait what? Didn't we just do this on Tuesday? The answer is no. On Tuesday we covered velocity, which is drastically different from speed. Let's explore.

Speed describes the rate at which an object is changing position, or moving through space, or any other medium, just like velocity. However, speed solely indicates the rate of change of motion. Nowhere in the speed can you find the direction of this motion. Consider the speedometer in your car. It tells you that you're going 65 mph regardless of which direction you are travelling. If it were to be coupled with a compass, and tell you, for example 65 mph, Northwest, you would then have a velocity.

Speed is what is known as a scalar, since it doesn't contain any of the direction information. Velocity is what is known as a vector quantity, since it contains the direction component as well.

Killer Resource: Star Talk Podcast hosted by Neil Degrasse Tyson

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Keywords: Position, Kinematics, Acceleration, Physics, Podcast, Derivative, Jerk

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09 January 2016- Jerk | PWN Physics 365

On this day in physics: 09 January 1942 Happy Birthday to Vladimir Steklov, "Steklov's primary scientific contribution is in the area of orthogonal functional sets. He introduced a class of closed orthogonal sets, developed asymptotic Liouville–Steklov method for orthogonal polynomials, proved theorems on generalized Fourier series, and developed an approximation technique later named Steklov function. He also worked on hydrodynamics and the theory of elasticity." (Source).

Jerk is the rate of change of acceleration, or how fast the change of speed is changing. Consider how you might feel sitting in the passenger seat of a car when someone steps on the gas versus lightly pressing the pedal. This is the difference between high and low jerk. It can be described mathematically as j(t), or a'(t), or v''(t), or x'''(t). Each of these mean the exactly same thing, which is that jerk is the third derivative of position, second derivative of velocity, and first derivative of acceleration.

Very interesting inference from wikipedia: "Because of involving third derivatives, in mathematics differential equations of the form

J(x''',x'',x',x')=0

are called jerk equations. It has been shown that a jerk equation, which is equivalent to a system of three first order, ordinary, non-linear differential equations, is in a certain sense the minimal setting for solutions showing chaotic behaviour. This motivates mathematical interest in jerk systems. Systems involving a fourth or higher derivative are accordingly called hyperjerk systems."

As jerk is the third derivative with respect to time, its units are length per second per second per second, or length per second cubed.

Killer Resource: Astronomy Pic of the Day. NASA's picture of the day.

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Keywords: Position, Kinematics, Acceleration, Physics, Podcast, Derivative, Jerk

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Episode 085b: Cross Product Example Pt. 2

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This second part of Episode 085 is going through a subtraction and cross product example, to just get the gears moving again after the New Year. Check it out!

Subtraction Example:

Cross Product Example:

08 January 2016- Acceleration | PWN Physics 365

On this day in physics: 08 January 1942 Happy Birthday to Stephen Hawking, the theoretical physicist and cosmologist best known for his work on black holes and for authoring the popular-science book A Brief History of Time. He also holds the once Newton-seated Luciasian Professorship at Cambridge University. (Source).

Word of the day: Acceleration is the rate at which an object in motion is changing its velocity, or how fast it is changing its change in position. It is typically described mathematically as a(t), or x''(t), pronounced x "double prime". The double prime notation is to indicate that it is the second derivative of position, or the change, or the derivative of velocity. Acceleration has units of length per second per second, or length per second squared. Humans are very sensitive to changes in acceleration. Massive objects create accelerations towards them because of their gravity. Because earthbound items are being accelerated towards the center of the earth at 9.81 m/s^2 when airborne, the acceleration due to gravity on earth is given the abbreviation g.

Killer Resource: A Brief History of Time. The most popular book written by our birthday boy above.

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Keywords: Position, Kinematics, Acceleration, Physics, Podcast, Derivative

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07 January 2016- Velocity | PWN Physics 365

On this day in physics: 07 January 1610 Galileo makes the first observation of four of Jupiter’s moons, which would be named the Galilean Moons after him (Source).

Word of the day: Velocity describes the rate at which an object is changing position, or moving through space, or any other medium. It can be described mathematically as v(t) or x'(t). x'(t) is said x-prime of t, which denotes that it is the derivative of the position vector. This is because the a derivative calculates the rate of change, and velocity is the rate of change of position. Velocity is also a vector quantity, meaning the direction of motion is also included in the information. The units for velocity are distance per time, in whatever unit you like. Common velocity units are miles per hour, meters per second, inches per second, kilometers per hour, the list goes on.

Killer Resource: Exploring Physics: Greek Letters. Free app that reviews all the greek letters in display, and flash card still. It's free, what do you have to lose??

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Keywords: Position, Kinematics, Velocity, Physics, Podcast

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