ENERGY EXPLAINED v2.1

[Farsight]

Many thanks LJP.

 

It's one of a (growing) set you know. See the RELATIVITY+ thread which hyperlinks to them in the right sequence.

[Farsight]

For reference, I've been tweaking things around a little. See next post for the latest version.

[Farsight]

ENERGY EXPLAINED v3.0

 

Can you explain energy to your grandmother? You might think you can, but don’t be too sure. Your explanation is likely to be no explanation at all. Your grandmother will peer at you over her bifocals, suck on her false teeth, say Thank you Dear, then get on with her knitting. She’s too polite to say it, because butter wouldn’t melt. But what she really meant is: Capacity to do work my arse.

 

 

Come on now, that’s no explanation. You swallowed that when you were a kid, and you haven’t looked at it since. It’s a basic concept, but your basic concept is just a label that covers up a hole in your understanding. It’s been there so long you’ve grown a thick skin right the way over it. Let me peel it back. To do that, I have to show you how you can think you understand something when you really really don’t. It’s all to so with The Psychology of Belief. OK, look at the picture below:

 

 

Now, square A and B are the same colour. I’ll say it again: square A and B are the same colour. Oh no they’re not, I hear you say. Oh yes they are, I say. Oh no they’re not you answer back. We could do this all day, but cut: I’m right and you’re wrong. They really are the same colour. The apparent difference in colour is an illusion. If you don’t believe me look through a hole in a piece of paper to remove the context that fooled you. Or get on the internet and look on eChalk: optical illusions and use the “swatch” to bridge the gap yourself. I’ve just found “Shades of Grey” at Thortz , good stuff, worth a read.

 

 

Anyhow, check it for yourself and then you’ll know that A and B really are the same colour. Surprised? Don’t be. The Psychology of Belief is incredibly powerful. It’s why we have religious cults who do crazy things. It’s why we have Young Earth Creationists. You can talk to them until you’re blue in the face but they are totally immune to logic because they are utterly convinced that they are right. The scarey thing is that they don’t know they’re immune to logic. These guys aren’t lying to you. Every point you make goes whoosh straight over their head, they just don’t listen, they dismiss everything you say, they just don’t have a rational open mind. But they don’t know it. They think they’re the rational ones, and you’re just some deluded crazy fool who just doesn’t know.

 

 

Do you know the real scarey thing? Most people are like this to some degree about something. Conviction is hard to crack. It’s the way we are, the way we think. Why do you think it took Einstein seventeen years to get a Nobel Prize for the wrong thing? And why do you think there’s that saying Catch ‘Em Young ? It’s because there are devious sly people out there who are fully aware that if you fill the little sucker children full of nonsense, they’ll carry on believing it come heaven or high water. These little sucker children remain so utterly convinced that they grow up to become adults who will fight and die for it. But we’re not going to fight and die for The Capacity to do Work. Because we are rational, we do have an open mind, and we do listen. We think for ourselves. We know that we need to look at our basic concept of what energy is and see if we can develop a better concept. Not perfect, just better. Let’s keep that open mind open.

 

OK, where were we? That schoolroom textbook told you that energy is the capacity to do work, and work is the transfer of energy. The words go round in circles without getting to the heart of it, and children grow into adults with no real concept of what energy is. So what is it?

 

 

Let’s start by saying that energy is the property of a thing. To illustrate this, I can talk about a red balloon, a red bus, or a red red ruby. All these things have the property that we call red. A thing can be red, but you cannot remove this red and hold it in your hand. You can remove the paint or the dye and hold that in the palm of your hand, but you’re still holding a thing that is red. You cannot remove the red from the dye to hold the red in the palm of your hand. Even when you imagine red, the image in your mind’s eye is a thing. You always need a thing to be red. There is no such thing as “raw red”.

 

 

You give a thing energy by doing work on it. You “put energy into it”. The parallel between work as in physics and work as in a job are quite striking here. One is to do with energy, the other is to do with money. Money is basically an energy token that everybody agrees about. Hence you can spend money like you can expend energy. But the money doesn’t disappear, just as the energy doesn’t disappear. Somebody else now has your money, just as some other thing now has your energy. Think about an old house, nestled in the countryside. It’s picturesque, worth a lot of money, and it’s built out of cob.

 

 

Way back when, some guy put some energy into shifting earth and straw to make the walls of this house. He did the same with the wood, which grew out of the earth because the trees put energy into shifting water and CO2. The guy made money out of that house. Somebody paid for the energy he put into it, through the work he did moving stuff.

 

 

But moving stuff around isn’t what energy is. That’s what it does, not what it is. And it does it to things, things that have mass. So we need to talk about mass and motion to talk about energy. Consider a 10 kilogram cannonball, in space, travelling at 1000 metres per second.

 

 

It's black, so you can't see it, sorry. We talk about how much kinetic energy this cannonball has. We say KE = ½mv² and we do the maths and get five million Joules. But what has the cannonball really got? Its mass seems real enough, I hefted it into my spaceship this morning before I took off. And its motion seems real enough too, because one false move and it’ll be smashing through my viewscreen taking my head off. To find out more, I take a spacewalk to place a thousand sheets of cardboard in the path of my cannonball. Each sheet of cardboard exerts a small braking force, slowing the cannonball to a halt. This takes two seconds. We know that the cannonball will punch through more cardboard in the first second than in the second second, because it’s slowing down. So we deduce that a cannonball travelling at 1000m/s has more than twice the kinetic energy of one travelling at 500m/s.

 

We can do the arithmetic for each second, then slice the seconds up finer and finer, and we end up realising that the ½v2 is the integral of all the velocities between v and 0. But what we don’t realise, is that kinetic energy is a way of describing the stopping distance for a given force applied to a given mass moving at a given velocity. You can flip it around to think about force times distance to get something moving. Or you can think in terms of damage. But basically that cannonball has “got” kinetic energy like it has “got” stopping distance.

 

It’s similar with momentum. That’s a different way of looking at the mass and the motion, based on force and time instead of force and distance. We look back to our cannonball and cardboard, and we know by definition that in the first second the same amount of time passed as in the second second. So we realise that a cannonball travelling at 1000m/s has twice the momentum of one travelling at 500m/s. But what we don’t realise is that momentum is a way of describing the stopping time for a given force applied to a given mass moving at a given velocity. A cannonball has “got” momentum like it has “got” stopping time.

 

But wait a minute. I didn’t fire the cannonball at 1000 metres a second. I dropped it off at a handy spot out near a GPS satellite, then zipped off in my spaceship in a big fat loop.

 

 

It’s me doing 1000m/s, not the cannonball. The cannonball is just sitting there in space. It hasn’t got any kinetic energy at all. I’ve got it. But I don’t feel supercharged with five million Joules of energy coursing though my veins. So where is it? Where’s the kinetic energy gone? It isn’t anywhere really, because all that cannonball has got, is its mass, and its motion. And that motion is relative to me. Kinetic energy is not a thing. It’s just a relative property.

 

So, let’s examine this property. How do you make something move? Easy. Hit it with something else that moves. And how did you make that something else move? Where did it all start? I pitch you a cannonball, you whack it with a baseball bat, and it tumbles away at one metre per second. You made that cannonball move. Now, where did the energy come from to make it move? From your muscles: “The release of ADP and inorganic phosphate causes the myosin head to turn, causing a ratchet movement. Myosin is now bound to actin in the strong binding state. This will pull the Z-bands towards each other. It also shortens the sarcomere...”.

 

 

It all gets a little complicated, but it’s all down to bond angles. Bonds within molecules change, and the change releases energy. Sometimes it’s a simple single change of bond angle, something like a leaf spring letting go and giving something a flip. Sometimes there’s more than one bond angle change, in a molecule that resembles an elasticated deck-chair surging from one configuration to another, giving up some of the bond energy. And sometimes the molecule takes a rather different shape. A familiar shape:

 

 

Collagen looks like a spring because it is a spring, that’s why it’s elastic. It’s in your skin. It makes your skin elastic. You see the same shape repeated in a great many organic molecules. It’s in your muscles too.

 

 

The molecules look like springs because they are springs. That’s the size of it. The energy to move your muscles is stored in tiny compressed springs. Yes, they’re electromagnetic springs rather than solid rigid springs, but let’s face it, that’s what all solid rigid springs basically are. They are electromagnetic in nature. That’s how the muscular energy is stored. It’s the same for chemical energy, and I quote:

 

"In the early 1980's it was pointed out that cubane's very high density and high heat of formation would make it an especially good explosive, especially if each carbon could have a nitro group attached. The resulting molecule would decompose to eight molecules of carbon dioxide, and four molecules of nitrogen, and release a lot of heat in the process. A cubane with a nitro group on each carbon is called octanitrocubane. Several factors are important in making a good explosive. The decomposition must be energetic. In cubane derivitives, the strain energy ensures a very energetic decomposition."

 

Did you get that? It’s the strain energy. There’s compressed “springs” in there. It’s the same with nuclear energy, only the “springs” are stronger. The sun gets its energy from nuclear fusion. Squeeze hydrogen atoms together and you make helium. But when you do, twang, something lets go, and things spring out between your fingers, things like photons. OK there’s a bit more to it than that because actually it’s a three-stage process and the recipe goes like this: 4 1H + 2 e --> 4He + 2 neutrinos + 6 photons. Here’s a picture. It’s worth a thousand words:

 

 

But it’s nice and simple for matter/antimatter annihilation. Take one electron. Add one positron. BANG. Somehow somewhere some kind of spring is letting go, and photons come bounding out at gamma-wave energies.

 

 

A photon is an interesting thing. Particle physics comes with mental baggage that says it’s a speck, a point, a particle. But we have long wave radio which reminds us that photons can be 1500m long. A photon isn’t a speck. It’s more like a slink in a slinky spring.

 

 

The slinky spring here is space, that vacuum void with its permeability and permittivity. A photon is a like a ripple on an electromagnetic ocean between the stars. A boat on this ocean can ride the ripple and the ripple passes on by. But tie that boat to the sea bed with a rubber rope, and you can capture the energy of the ripple, and save it in starch, or coal, or oil.

 

 

But space isn’t really an ocean. It doesn’t have a surface, it isn’t a liquid, and there’s no substance to it. Mathematically speaking, space can be modelled rather like a block of ghostly electric rubber. And a photon is a stress travelling in it, a transverse wave of vacuum electric stress. A tree can capture a photon via photosynthesis and use it to make leaves and branches, and then you can use them to build your house. It all comes down to springs, elasticity. The energy is in the compression, the pressure, the stress. And in the end, this stress is somehow in space itself.

 

It’s not obvious. You don’t always realise it’s there. But then you get a Phase Change, and something happens. Then you realise it was there all along. Like you realise that the cool air was moist when the water vapour condenses out and it starts raining warm rain. Sometimes it’s more dramatic than that. Sometimes it’s called Symmetry Breaking. It’s rather like a big hidden spring letting go everywhere. The Big Bang was something like that. The “prime mover” dumped a fireball rain of nuclear and electromagnetic energy that makes the world what it is.

 

 

All these springs and elastic are just analogy of course. Analogies are based on the tangible things we experience with our senses, and these are not the things of the subatomic world. So analogies can be dangerous, like too much butter. But the Universe will wind down, the stresses in space will eventually even out. Because that’s what energy is. Stress. It’s the same thing as pressure, which is the same as negative tension. And to quantify it we have to know that in physics, stress is force per unit area, and energy is force times distance. We have to multiply by an area and then by a distance, so we have to multiply by a volume. So energy is stress times volume. And here’s the new definition:

 

Energy is the capacity to do work, and is in essence a volume of stressed space.

 

You know you can’t hold stress in the palm of your hand, and a volume of it doesn’t make it something you can get hold of. That’s why you can’t hold pure energy in the palm of your hand. There is no such thing as “pure energy”, just as there is no such thing as “pure pressure”. Because it’s the property of a thing, even when it’s the very last property that makes a thing the thing that it is. But you can hold energy in your hand. It’s a subtle difference, but it’s very simple. Just squeeze a fist. Use your right hand. Squeeze it tight. Now touch your left thumb to your right thumb. Feel that blood pressure. Now look at the volume of your fist. Stress is pressure, and there’s a volume of it in that fist. Your fist has energy. And if you swing that fist, it has even more. As to how, it’s all to do with pushing little circles into little spirals and making little springs. But to explain that, I’ll have to explain mass.