Cosmospostman’s Introduction To Energy 1

People discuss energy every day – renewable energy, energy independence, energy stockpiles and ultra-cute, high-energy black puppy dogs are a few examples I can think of right now.  Everyone talks about it, but few people know what it really means.  My sister did a year 9 Science report on Energy – and while promising to furnish us with definitions, provided nothing more than a comparative review of coal vs solar vs biofuels vs whatever.

Given that ‘energy’ is such a key player in this modern life of ours, I think very few people have a grip on who this slippery fellow called Energy really is.  Let me personify: she’s a moderately attractive brunette in a tight black leather jacket employed by the Moscow Circus as a contortionist.  No – he’s an old granddad gliding swiftly along on a motorised scooter, flatuating in the hot summer breeze.  Actually, some have even reported Energy to be the fat lady behind the counter at the local school tuckshop [canteen] serving meat pies to the twelve year olds.  Point is, energy takes many forms, and is hard to pin down and identify.  So I’d like to get up on my soap box and expose the true identity of this 21st century fugitive.  Did I mention he’s invisible?

What exactly is energy?

Let’s start with a loose definition: “Energy is the ability of something to ‘push’ (or pull) other things, ie, to apply to an object some force over a distance“.

That little boy's got energy! (CC licenced)

It’s all about being able to push.  If you have energy, it means you can push things – simple as that.  If you have no energy, you can’t do anything at all.  More on that later, but for now imagine you’ve come home from a long hot day on the mango paddock and you’re completely buggered.  You slouch down on a chair and vegetate.  Mother Dearest yells from the kitchen, ‘for the seventh time, somebody bring those bloody clothes in off the line IMMEDIATELY or I’m going to hit the roof!!!!’ (not really).  You reply, ‘but mum, I’ve got no energy!  I can’t do that! Triangulate and chillよ!’  What you mean to say in a more technical sense is, ‘Oh, I’d love to lend a hand Mother Dearest, but I’m physically incapable of doing so because I’ve got absolutely no energy left in me whatsoever. What that means is, I completely lack the ability to remove the clothes from the line, and furthermore, am unable to apply force to the clothes trolley over the distance it takes to push it back to the house. I’m so sorry.  I’m sure my sister can lend you a hand, though’.  Energy means you can push things.  If you can’t push things, you can’t do anything.  Recapitulation of ‘force through distance’ and ‘push is everything’ later, but I’m hoping that’s enough for now.

Types of energy

Energy comes in two varieties: kinetic (moving) and potential (could be moving), assigned the symbols K and U respectively.  Kinetic energy means, ‘because an object is moving, it is able to push things’.  Just picture a pedestrian being pushed over by a moving car.  Potential energy means, ‘While not moving, an object is still able to push things due to the situation it is in’.  Imagine lifting weights above your head, and how in such a situation they have the ability to push down on you.  If that doesn’t work, imagine Stephen Conroy [link] pushing a pile of poo [link] up a hill.  He’s half way up and stops for a breather.  Even though the poo is not moving, it has gained some gravitational potential energy.  In other words, the poo now has the ability to push back down on Conroy, which is what will happen unless some restraining force is placed upon the poo in the meantime.

Every type of energy can be categorised into either kinetic or potential.  Here are a few examples:

• Kinetic:
  • Translational, if the object is moving in a line
  • Rotational, if the object is moving in a circular fashion
• Potential:
  • Gravitational, due to interactions between two or more bodies with mass
  • Electrostatic, due to interactions between two or more bodies with charge
  • Spring/Elastic, the energy stored in a stretched spring or rubber band
  • Nuclear (aka Chemical), where energy is stored in the electron configuration of an atom. Little to do with nuclear power.
• Special cases:
  • ‘Thermal Energy’, or Heat, is merely the vibrations of an object’s constituent atoms (energy here oscillates between potential and kinetic)
  • ‘Food Energy’, is the same as Nuclear Energy above.  Digestion of food is a chemical process which ultimately leaves the body’s electrons in a higher state of energy.

Dear reader, I challenge you to suggest a type of energy that does not fit into either the Kinetic or Potential category.

How Energy Exists

Evan has many golf balls.  Penny has gained a lot of respect recently.  Intrabella lost her booze cache.  Alfred has energy.  Here, as is the case most of the time when communicating in English, there is a sense of ‘active possession’.  If you have something, like golf balls or booze, you can hold it.  Make an effort to get it and it’s yours.  It belongs to you.  Even intangible things like respect need to be earned, and one could in a way consider themselves to be an ‘owner’ of some respect.  I just wanted to clarify that feature of language before asking, how does something attain the ability to push?

One answer to such a question would reference the transfer of energy, ie. something else pushing on you and you gaining energy.  While accurate, I find that such an explanation to be self-referencing, not to mention revealing little about the nature of energy.  Instead, I offer reasoning based on the notion of ‘passive possession’:

Is a watermelon the same at the bottom of an elevator shaft as it is at the top?  Yes, in fact I could take the watermelon up and down the elevator all day and it would not change one bit.  Barak Obama was reportedly caught saying during his recent election campaign, “You can take a watermelon to the top of an elevator shaft, but it’s still a watermelon”.  This infamous quote caused a considerable amount of outrage in the watermelon industry, and amongst Republicans – who misinterpreted this statement as a jab at Sarah Palin’s watermelon-like qualities (whatever they happen to be).   However, the energy (in particular, gravitational potential and kinetic) of the melon varies as I move up and down the building.  It seems that watermelons remain identical with themselves no matter how much energy they have.  How, then, can a watermelon have energy?

Low and high energy watermelon (CC Derivative)

I would argue that having energy is different to having golf balls and booze.  A person with lots of alcohol is physically not the same as a person without alcohol, where as a body physically remains the same no matter how much energy it has.  The way I see it, you have energy due to the situation you happen to be in, quite different to wearing a backpack full of goon.  Energy is really just circumstantial.  As such, it may be confusing to refer to a ‘quantity of energy’.  Furthermore, the idea of ‘energy possession’ is actually misleading – ‘state of energy’ or even ‘level of energy’ do a better job of taking stock of the situation, because objects don’t really have energy; rather they have the attribute of energy associated with them due to their predicament.  The exception to this way of thinking is Chemical energy, which comes about by moving electrons inside an object so that they are better poised to push.

Simply put, energy, rather than being intrinsic, arises from situation.  It doesn’t really exist in the sense that it’s more of a concept than a physical entity.

Applicability of the model

Let’s stop and think.  To do almost anything in this universe, you need energy, right?  By our definition, this means push is involved wherever energy is.  Let’s see… setting something in motion requires you to push it, either directly or by way of force-at-a-distance (like gravitational or electrostatic pull).  Remember that once in motion, bodies remain in motion unless an external force acts on them, which is why space probes such as the Voyager twins continue speeding off to galaxies far, far away, even after flying through space for over 30 years already.

‘Electricity grid’ is the name given to a regime that pushes electrons through wires all day long.  On a smaller scale, computers need energy – for they need to push electric charges around a circuit board in order to store and operate on information.  Similarly, biological thought requires that electric pulses be fired (pushed) from neuron to neuron inside the brain.  The production of sound requires air molecules to be pushed into a state of vibration, and the propagation of a sound wave is nothing more than air molecules pushing on each other.  Can you think of any action that does not require push?

Summary

1. Energy is the ability to push or pull things (apply force through distance)
2. The ability to push arises from an object’s position in regards to its surroundings
3. Push/pull is at the core of all action
4. Energy is classified as either Kinetic or Potential

I posted this with the intention of being clear-cut and simple, so please tell me if your reading experience suggests otherwise.

PS. Bumdom, I have matched your previous post; burden of reciprocation is now on you

PPS. Changed the theme to one which gives more text per row and a better font, on my browser anyway.