Response to Zeno’s Arrow Paradox

1 10 2010

“The Arrow.  Does the arrow move when the archer shoots it at the target? If there is a reality of space, the arrow must at all times occupy a particular position in space on its way to the target. But for an arrow to occupy a position in space that is equal to its length is precisely what is meant when one says that the arrow is at rest. Since the arrow must always occupy such a position on its trajectory which is equal to its length, the arrow must be always at rest. Therefore motion is an illusion.”

I don’t know about you but I had to read this eight times to “figure it out” and I’m still not sure I understand it because it is poorly written.  It says “a position in space that is equal to its length”.  A position is a portion of space occupied by something, or a point/location.  He’s equating a three-dimensional space or a point to a line (length).

After proving to myself this is not correct, I Googled Zeno’s paradoxes and found all kinds of lame reasons why this is incorrect, including the arrow can be in motion at an instant, but not in and instant.  Suddenly, I may see why Clinton under testimony questioned, “It depends on what the meaning of is is.”  This is a bunch of hair splitting by people who don’t understand physics.

Here is my answer in less than 50 words:

For anything to start, stop, accelerate or decelerate there is deflection of the object even though it may be infinitesimal.  Therefore, the arrow DOES NOT take up precisely the same space or maintain its exact length.

End of answer.

When the archer lets go of the string, the energy transferred to the arrow compresses it linearly.  The string continues to exert force on the arrow but when the arrow departs from the string it lengthens like a spring.  On its way to the target I guarantee it is vibrating along the length of shaft at least for some period of time.

Throw a water balloon; it will clearly deflect possibly to the point it bursts.  Throw a baseball and it will deflect as well and so will your fingers.  You can find plenty of snapshots of golf balls being smushed.  If the object that is acted upon cannot absorb all the energy, it breaks or splits, but it will move first.  Even putting something in motion by gravity will change shape.  Anything stationary sitting on the floor, roof, or table is deflecting to some extent under its own weight.  Roll an egg off a table sometime and watch it deflect on the floor.

written by Jeffrey L. Ihnen, P.E., LEED AP

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Taking on Parmenides

23 09 2010

We do a LOT of energy efficiency program evaluation and measurement and verification work all over the country; make that North America.  Program evaluation consists primarily of process evaluation (process) and impact evaluation (impact).  Our work is almost entirely in the impact side and I know just enough to talk dangerously about process.

Impact is the analysis of what energy savings are really attributable to the program.  This includes verifying the physical installation and determining the actual savings using some sort of engineering analysis.  This actual savings is known as gross savings in the business.  It also includes determining whether the program actually influenced the project to happen.  For example, some would do a project or buy an efficient piece of equipment regardless of the program and just take the money because they can – and hey, they are paying into the program so there is nothing wrong with this in my opinion.  These program-influence factors are applied to the gross savings to determine net savings – savings the program can take credit for.

Largely, evaluation teams consist of economists (impact and process) and engineers (impact) although there are many people with liberal arts degrees in the business as well.

Many times in determining the gross savings we get into spats with program implementers and sometimes utilities regarding what the actual savings really are.  Many times for large custom projects, the energy analysis we have to evaluate varies from pathetic to essentially non-existent.  “We installed a control system.  Savings = 15%.”  That’s it.  Analyze that!  Other times we will have an actual analysis and just plainly an incorrect application of engineering and physics or the operating conditions are much different than originally assumed.

Last week we were preparing to do impact for a huge low income weatherization program.  Past evaluations for that program have turned up results that are only a fraction of what the utilities think they ought to be.

Consider how to estimate heating savings in this case.  A house is heated by natural gas, which is also consumed by other appliances including possibly a stove and a water heater.  The analysis is easy.  You can see on the monthly billing data (gas consumption) how much gas is used to heat the place.  It’s everything above the June through July average.  Savings in this case are more or less proportional to the consumption for heating.  It is as plain as the nose on your face.  But the utilities think otherwise.  While I certainly don’t want to arm them with any arguments, they could use Parmenides, the 2500 year old and dead philosopher.

I took a four credit philosophy course as an undergrad.  The discussions in class seemed bizarre but definitely thought provoking.  If you haven’t studied or read philosophy, you would most likely think it bizarre.  But I am far, far, far (way far) from an expert on the topic.

One thing I remember discussing at length was, what does it mean for a being to be?  Is there really anything that exists other than your mind?

I had to do some “research” to find philosophical terms.   I’m talking about idealism.  Idealism is the argument that your mind is all that exists and that the world is mental itself or an illusion created by the mind.  Sound bizarre?  Not so much if you think about it.

You’ve probably seen the HDTV ads that have stuff jumping out of the screen – like the picture is so real viewers purportedly see footballs flying out of the TV, right at them.  Consider a person comes into my office and I ask him what he sees out the window.  After a looking around to make sure he’s not on candid camera, the answer is: Coney Island hot dog joint and Deaf Ear Records.  “Really?”, I respond.  How do you know?  I can see it.  How do you know it’s not just an illusion?  How do you know it’s not the world’s most expensive and lifelike television?  Good God!  I can go downstairs, cross the street and touch it.  What more do you want?  I can prove motion is an illusion and that you won’t really go anywhere, much less get out of this room, but that’s beside the point right now.  So go ahead and touch it.  What does that tell you?  Why do you call it Coney Island?  It says so.  Really?  How do you know?  I can read it.  Read what?  By touching it?  Why don’t you ask that guy who just got off the plane from Moscow what it says?  You can’t prove anything.  It’s all an illusion formulated in your mind.

The sky is blue.  OK.  But what if blue in your figment-of-imagination world would be green in my world?  Who is ever going to know?  We can both look at the same color and declare it to be the same thing – yeah sure, it’s blue.  But a color is a color only because somebody told you so way back when and you correlated it to what you saw and it has been as such ever since – in your fantasy world.  What is the definition of blue anyway?  My dictionary defines it in part as the color of a clear unclouded sky.  Great.  That doesn’t explain anything.  What color is a blue car under a clear unclouded sky… AT NIGHT?  Why don’t you ask that color-blind 100 lb rodent that is eating the seedling I just planted what color his snack is.

This brings me back to the illusionary energy savings.  Now that we know energy savings like everything else is all an illusion anyway, we can fool ourselves and put any number to it that we want.

Quite possibly, the program evaluation industry may be a gold mine for out-of-work philosophers and theologians!  Utilities could have a team of philosophers to take on the evaluation team’s philosophers.  Engineers and economists on the evaluation team would argue with their counterparts on the implementation team regarding the illusionary savings and the philosophers could duke it out over… something.  See what I’m sayin?  If so, it’s just a figment of your imagination.  These people only exist in your mind.

Epilogue

For more on Parmenides, see this article, and in particular the Achilles and Tortoise paradox.  Since learning that we still earn vacation while taking vacation (eons ago), you never need to return to work.

I earn roughly 3 hours of vacation every week.  So if I take a week off I’ve used 40 hours but earned another three.  I’ll take those three Monday morning, but I’ve earned 0.225 hour during those three hours.  While I take that 13.5 minutes of vacation, I earn another minute.  And it goes on forever, like eternity.  Now do you think this philosophy stuff is stupid?

Contest

Above I said I can prove motion is an illusion.  That was a lie, at the time.  Since I’m telling you it was a lie, it isn’t, is it?  On “The Big View” website, number 3 from Zeno attempts to prove motion is an illusion.  For $10, explain why his hypothesis is wrong.  The best answer wins, unless they are all horrible.  Prize money will be split in case of a tie.  If there are 10 or more correct answers, it wasn’t difficult enough so no prize.  Contest ends September 30, 2010 AD.  Send responses to kjk@michaelsengineering.com.  There is a 50 word limit.  Responses that are too long will be rejected.

written by Jeffrey L. Ihnen, P.E., LEED AP





Jacque – Fix My Car

3 02 2010

There is a running joke in our business that electrical engineers don’t know anything about energy efficiency.  It is only a joke.  One of the sharpest energy guys I have interviewed was a physics major who started on the ground floor of an energy efficiency consulting firm filling orders of equipment they also happened to sell.  In 10 years he worked his way up to really understanding how buildings and their complex systems work and he became a manager of a team of energy engineers teaching his group how buildings work and how to model them.

This article made laugh out loud.  MBAs developing energy management plans and reducing businesses’ carbon footprint.  Maybe I need an MBA to consult with my doctor prior to my next gallbladder surgery.  I can see it now.  Replace lighting in a half million square foot manufacturing plant (nothing wrong with that) and install 100 kW of photovoltaic and dedicate a focus group to reduce energy consumption.  Meanwhile there are what we call piles of cash ablaze scattered about the plant in the form of process, system, and controls waste, on both the supply and demand ends of energy consuming systems.

Beyond shutting things off and installing equipment that is more efficient than option A, energy efficiency is domain of the physical sciences.  The root of energy efficiency expertise is calculus, followed by physics, and core courses in thermodynamics, heat transfer, and fluid dynamics.  If job candidates have anything less than Bs in any of these courses we discard them as candidates.

Arm an engineering graduate with an MBA and you may have a powerful weapon to put out these fires.  An MBA could make a rousing case to embrace energy efficiency as a profit enhancer, risk reducer, and marketing tool – much better than I can.  But there are already enough engineers in our business who don’t know what they are doing.  We evaluate their work all the time.  We don’t need political scientist MBAs cluttering up our market.  I might as well look up a culinary chef to do a wheel alignment on my car.  Jacque Pepin, are you available?

written by Jeffrey L. Ihnen, P.E., LEED AP