Quantum Discomfort

Quantum physics has always been this mystical thing to me.  Throughout my years of academic studies in engineering, the word quantum may have been uttered by a professor, but it was never explored in any kind of depth.  Engineers are practical, and while quantum physics is fascinating, it is of little practical importance to most engineers at present.

A physics professor might say, "Classical physics is not theoretically sound, as it is only an approximation, and may only be accurately applied to things that do not move too fast and are not too small."  An engineering professor might then respond, "Most things are reasonably large and move reasonable slowly... In any case, any error less than 5% is good enough for me."

For nearly all engineers, the entire field of study may be ignored, and is.  For theoretical physicists on the other hand, it appears that there is not much outside quantum physics to ponder anymore.

In reality, for an object of reasonable size, the amount of error introduced by simply ignoring quantum aspects is negligible.  Still, this field of study is so fundamentally different from all of the science that came before it, that it is always categorized separately; that is, there is quantum physics, which centers around wave functions and probabilities, and then there is classical physics, which is everything else.

Quantum physics as a field of study was established in the mid-1920s with physicists such as Max Planck, Albert Einstein, Neils Bohr, and Werner Heisenberg.  The fundamental principle of quantum physics was discovered by Heisenberg, who showed that one could not be 100% certain of both the momentum and position of a given particle.  The law is known as the 'uncertainty principle', not to be confused with the 'what the heck is going on principle' commonly exemplified by certain physics students.  

Wavelengths and Personality Types

Light is a funny thing. 

It behaves like an electromagnetic wave (it has a phase - it can undergo interference), yet it also behaves like a stream of particles (it consists of photons, as proven by Einstein's photoelectric effect).  The split personality exhibited by light has bewildered scientists for one hundred years.  And, while we will never see a photon with our naked eye, our eyes would see nothing at all if not for light.  These photons reveal the nature of the matter around us, but keep their own true nature under wraps.

The light that reaches our pupils may come directly from a source or it may arrive after a series of reflections off of other surfaces; either way, the light emanates from a source, like the sun or a light bulb.  Both of these particular sources produce what is known as white light. 

All electromagnetic waves, whether they are radio waves or x-rays, have a wavelength associated with them.  Visible light fills a very narrow band within the electromagnetic spectrum: 400 nm to 700 nm.  All wavelengths in this range correspond to a particular colour.  Violet light has a wavelength of 400 nm, while that of red is 700 nm.  A rainbow will have these colours on either side (violet on the bottom, red on top), and all other colours in between ordered by wavelength.  White light is what you get if you superimpose all colours in the visible spectrum on top of one another.  Black, on the other hand, represents the absence of colour.

With this background information on light, we can properly appreciate why a red sports car looks like a red sports car.  It is less obvious than you might think...

The sun undergoes fusion, a nuclear reaction, which produces, among other things, white light.  These white light rays travel in all directions at about 300,000 km/s.  After travelling a little over eight minutes, some of these white light rays hit the red sports car that sits before you.  Then, something critical happens: some of the white light is reflected by the car's surface, but most of it is absorbed.  In fact, the surface absorbs every wavelength of light with the exception of its own, red, 700 nm.  The 700 nm wavelength of the light is reflected by the surface.  These reflected light rays head off in many directions, including yours.  Your brain interprets this wavelength to be red.

So, while the car may be red, we could not make this deduction if not for a source of light that contains, at a minimum, this particular wavelength.  It is kind of like that falling tree... If an object is not lit up by a source, does it have a colour?

The car's red colour gives it a certain character.  And, while one's personality is more complex than a single data point along a spectrum, colour codes for personality classification are often surprisingly telling.

High Pressure Situations

A relatively small number of people deal with intense situations on a regular basis.  Overseas military, first responders and ER doctors are part of a select group that deal with high stress on a daily basis.  The rest of us can probably count on one hand the number of traumatic experiences that we have encountered in our modern, sheltered lives.  Personally, I can count this number on two fingers.

The first intense situation that I recall occurred when I was eighteen and living at home.  I started the backyard barbecue, and then went back inside the house while it warmed up.  When I looked back at the barbecue a few minutes later, it was a massive fireball.  I jumped to my feet, and ran towards the fire extinguisher.  As I approached the fire, I was fearful, realizing that the propane tank could have blown up at any moment.  Nevertheless, I sprayed out the blazing flames.

My one and only firefighting experience ended well.    Thinking back now, my actions that evening were instinctive; they involved no thought.  Intense situations do not leave one with much time to think.

Intense situation number two made yesterday a day I would like to forget.

Differential Equations Govern the Future

Mathematics is the language used to quantify anything in science.  Still, some aspect of the tool we call math is utilized in nearly every field from business, to sales, and of course, engineering.

The field of Mathematics may be divided into several branches like calculus, linear algebra, and statistics.  While all of these subjects are fascinating, let us focus on calculus, which can be summarized as "the study of change."  If no facet of the universe ever changed, we would have no use for calculus, but then again, such a universe could not support life altogether (life cannot exist without chemical reactions).

At its heart, calculus focuses on functions, which are equations describing how variables are related to one another.  The simplest kind of function consists of two variables; one variable is dependent, the other is independent.  If a taxi driver charges a customer $1.50 per minute, then the cost function for riding in the taxi would be C = 1.5t, where C is in dollars and t is in minutes.  Here, time is an independent variable, and cost is a dependent variable (as the cost depends on the duration of the cab ride).  In other words, cost is a function of time, or C = f (t).

The simple taxi function given above relates cost to time, but functions can describe the relationships between other dependent variables and time.  We could, for example, consider the temperature of a hot cup of coffee.  One can imagine that the coffee's temperature value would decrease as time goes on until it reaches the room's air temperature.  The key difference between the taxi function and the coffee function, is that the function for the ride in the taxi was specified by the taxi driver.  No one specified the temperature function of the coffee.  The coffee's temperature function is the result of a differential equation, which is also known as a governing equation - a law of nature, and in the case of the coffee, thermodynamics.