Tag Archives: Physics

Hysteresis Explained

Hysteresis (hiss-ter-ee-sis). Lovely word. But what on earth does it mean?

Hysteresis is one of those typically jargonny words used by scientists that instantly renders the entire sentence if not lecture lost on its audience. Sure, you can look it up on wikipedia, but you may die of boredom before you get to the point, so I am going to explain it here.

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Hysteresis on the way to school

Let’s go for a walk. Let’s say we are ten years old and we are walking to school. The route is simple. The school is a few hundred yards down the hill on the other side of the road. Now consider the question: at what stage do we cross the road? Immediately? Or do we walk all the way to opposite the school before crossing – or somewhere between?

Assuming there are no ‘official’ crossing points, I bet you cross immediately, then walk down the far side of the road.

How can I make this prediction? Well, I assume that crossing the road requires there to be no traffic, so if there is no traffic as you start the journey, it is a good time to cross. If there is traffic, you just start walking down the road until a gap appears, then you cross. This strategy allows you to cross without losing any time. If your strategy had been to cross at the school there is a real risk you will need to wait, thus losing time. So it turns out the best strategy to avoid any waiting is to cross as soon as you can.

So now picture your walk home. Again, it makes sense to cross early on. The result is that the best route to school is not the same as the best route from school. This is an example of hysteresis – or a ‘path dependent phenomena’.

Hysteresis  everywhere

The dictionary will drone on about magnetism and capacitance and imaginary numbers. A much nicer example is melting and freezing of materials – some substances actually melt and freeze at different temperatures. This shows that the answer to the question: “is X a solid at temperature Y?” actually depends – on the path taken to that temperature. Just like what side of the road you are halfway between home and school will depend on whether you are coming or going.

It seems to me that falling asleep and waking up also bear some of the hallmarks of hysteresis; although they could be considered a simple state change in opposite directions, they feel very different to me – I  seem to drift to sleep, but tend to wake to alertness rather suddenly.

Now think of a golf club in mid swing. As the golfer swings, the head of the club lags behind the shaft. If the golfer where to swing in reverse, the club head would lag in the other direction – thus, you can  tell the direction of movement from a still photograph. We can therefore say the shape of a golf club exhibits hysteresis – and again you see see why it is so-called “path dependent”.

This logic can be taken further still – wetting is not the opposite of drying and likewise heating is rarely the inverse of of cooling. Let’s imagine for example that you want to make a chicken pie warm on the inside and cool on the outside. This is best done by warming the whole pie and then letting it cool a little. The temperature ‘profile’ inside your pie thus depends not only on the recent temperature but has a complex relationship with its more distant temperature history. This particular point is somewhat salient at the moment as we ask the question: is the earth heating up? 

So what?

Good question. I’m not a fan of jargon, and hysteresis is not a word I hope to need to use in my smalltalk. However, you can see that it encapsulates a rather specific and increasingly important concept that is pretty hard to replace with two or three simpler words; thus it passes my test of “words a scientist should understand that most don’t”. Please let me know your own additions to such a list!

 

 

Could Google Earth Show Sea Level Change Impacts?

I just finished reading Storms of my Grandchildren by James Hansen – it is basically an alarming presentation of evidence that not only is climate change affected by humans, but that the changes could indeed be dramatic and soon. While the author warns of effects more extreme than the ‘consensus’ of the IPCC, he argues very credibly. It is worthwhile to note that in achieving consensus, any group needs to ‘normalise’ opinion (i.e.  compromise).

The IPCC cannot say “all is well”, as there is undeniable evidence that it isn’t, and they are, after all, a bunch of tree huggers (said with love!) .

However, it cannot say “ban all coal” either, because it would render itself at odds with governments, and find the party invitations will dry up sharpish. The IPCC said what it had to say from day one: there is a massive risk of disaster and we need to find a pragmatic way forward that does not punish any sector too harshly.

It also appreciates that it needs to gradually adjust the Zeitgeist. Each report will get more draconian, not just because the evidence is getting stronger, but because the audience is softening up with time. Of course, this public opinion inertia takes up time, which is exactly what we haven’t got.

James Hansen, is therefore now acting as a representative for those who feel the urgency is lacking. He accepts that his invitations to the Whitehouse may have got lost in the post of late, but he is gathering a following and starting to get heard.

Anyway, on to my point. While reading the book, I realized not only the lack of action against climate change, but also the lack of action to prepare for it.  I read up on what various people are thinking (including the IPCC take), and I was wondering how much the individual can do.

In a slump of morbidity (you read the book, you may have one too), I wondered how my town may look if sea levels does rise a few meters. It is not too hard to trace out the new shoreline, but it did make me think I could write a program that could plug into Google Earth in which you could dial in the sea level and take a look.

Initally I thought I might get lucky with new sea views to look forward to – then I realize my house would be completely unaccessible and my local town would be gone, along with my friends and also most of the roads…

Perhaps I should start saving for a nice big boat?

PS. Feed your obsessive-compulsive side – take a regular look here: http://arctic.atmos.uiuc.edu/cryosphere/ . Is this a good canary in the coal mine? I hope not! There is an alarming dip the last few days – (today is Dec 23, 2010) –  tell me it was a blip! Did I mention looking at this daily will lead to the complete abandonment of statistical sense and every blip will be a crisis? I mention it now…

Stuff I Wish I Had Read When I Was Younger

Over the years I have supervised and mentored several PhD students, and recently our firm started to award scholarships to undergrads, and I was asked to support one such scholar. These scholars are from the best and brightest and so I got to thinking…

Graduates today have it tough, competition is tough, people work longer and harder than ever and stress is hitting us earlier and earlier in life – or so it seems. I would argue that, to some real extent, things have always been getting worse, and therefore by induction, we can prove that they have haven’t really changed at all.

No, the graduates of today have unparalleled opportunity to learn, to travel and to experience. The brightest graduates have the world at their feet and will be its commanders when we are are all retired and done for.

So what could I do to support this scholar? In the end it was easy – I asked myself – what do I know now that I wish I had known sooner? Most of this is in attitudes and is deep in my psychology, and is the result of direct experience – but it turns out that a healthy chunk of my scientific learning experience can be re-lived – by reading some of the books I think steered my course.

So I made a point to summarize some of the best science related books I have read (and some of the most useful internet resources I have found), and dumped the list complete with hyper-links in an email to the scholar. I hope she goes on to be president!

Now having gone to the effort, it would be a crime to keep this email secret, so here it is, (almost) verbatim!

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As promised, here is a list of useful resources I wish I had known about when I was an undergrad. I am glad I got round to this, it should be useful for several other students I work with, and has also led to me revisiting a few things! I think I may brush it up and pop in on my blog if you don’t mind…obviously I won’t mention you!
Anyway, back to the business. To me, science is not all about chemistry, molecules, atoms, valence electrons and so on. To me, is is the process of trying to understand the world, and this set of materials I have hand picked, should you get through even a part of it, will not only educate but inspire.

This may not be the very best list, and I am sure there are many great books I have not read, but I have stuck with ones that I have, so you will have to rely on other people for further recommendations.

Jarrod’s reading list: science/psychology/economics & so on

  • I’ll start with something really easy, relevant and engaging – an excellent (if quirky) summary of material science: The New Science of Strong Materials – Prof Gordon  has written another on Structures that is also worth reading.
  • Ok, this next one is not a book, but a paper; I like it because it shows that many stuffy professors are wrong when they prescribe boring scientific prose for papers. This paper uses the criminal “us” and “we” and discusses subjects as if with a friend. Shocking form, especially for a junior scientist. This paper by an unknown, changed the world.
  • Guns, Germs and Steel” – this is large-scale scientific thinking at its best- the book looks at how we can explain why the world is the way it is (especially the inequality) by looking at how technology spreads through societies.
  • Mistakes were made…but not by me” – this is required reading if you want to work with other people, so its basically for everyone then…
  • Then to take it to the next level – “How the mind works…” – Stephen Pinker‘s other books are also good if you like this one.
  • “Flatland”, (full text here) was written in 1884, and is essential reading because it defines the cliche “thinking outside of the box”.
  • To make your upcoming economics courses more interesting, first read this easy-to-read popular book: “The Undercover Economist“.
  • Also, Freakonomics– it’s shameless self promotion by egotistical authors, but hell they are smart, so put up with it.
  • The Tipping Point –  Malcolm Gladwell is a current thinker I really like; he’s not satisfied to focus on one thing for very long – his other books are on totally different stuff, but are equally thought provoking.
  • The selfish gene” – Obviously I would firstly recommend “On the Origin of Species”, (full text here) but if you are short of time (which you should be as an undergrad), you can learn most of the basics, and also get updated (well up to the 1970’s at any rate) by reading Dawkins’ classic.
  • I couldn’t ignore statistics, so I will include two – one classic, “How to Lie with Statistics”  and a more modern one “Reckoning with Risk“, they are quite different, but either will get the important points across.

Alas, books are perhaps becoming obsolete, so I better include some other media:-

  • The first one is so good I can’t believe its free – try watch at least one a week, but the odd binge is essential too. http://www.ted.com/
  • Next, an excellent physics recap (or primer) – but  you need lots of time (or a long commute!) to get through this lot – look on the left menu for Podacts/Webcasts on this webpage: http://muller.lbl.gov/teaching/physics10/pffp.html – I cannot begin to praise the worthwhileness of this enough. It used to be called “Physics for future presidents” because it teaches you enough to understand the risks of nuclear energy, and the likelihood that we will all run our cars on water – and let you know when you are being duped or dazzled by big words.
  • When I was somewhat younger there was a TV show called Cosmos, hosted by Carl Sagan, you may know of it. You could watch in now here, though obviously it is dated, so perhaps you shouldn’t; the reason I mention it, is because it was key in creating a generation of scientists, people who were inspired by Carl to be inspired by the universe. The previous generation had the space race and the moon landings to inspire them, but since then science has been on a downhill, with 3-mile island, global warming, etc, etc, and we have had no more Carl Sagans to cheer for us; Cosmos was a rare bit of resistance in the decline of the importance of science in society. You may also know that there have been battles in society (well in the circles on intelligentsia at any rate) about science – on the one had the ‘two cultures debate‘ and more recently, the ‘anti-science’ movement (suggested in books like “The Republican War on Science“. I do not wish to indoctrinate you, but rather make you aware that being a scientist used to be cooler and used to be more respected and something is indeed rotten in the state of Denmark.
  • Getting back on track, here is an excellent guide to critical thinking (something else sadly lacking in the world) – don’t read it, listen to the podcast versions (also on itunes):
    “A Magical Journey through the Land of Logical Fallacies” – Part 1 and Part 2
    I think this should be taught in school. Brian Dunning’s other Skeptoid podcasts put these lessons into practice showing how a scientific approach can debunk an awful lot of the nonsense that is out there (alternative medicine, water dowsers, fortune tellers, ghost hunters, etc etc).
  • If you do happen to have any time left, which I doubt, there are several other podcasts on critical thinking – that use a scientific approach to look at the world and current affairs: –

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Postscipt – Dear readers, please feel free to append your own recommendations to my letter in the comments section below. If there is one thing I know well, and that’s how little I know. I feel I only started to read ‘the good stuff’ far too late in life, and so those with more years than me (or better mentors), please do share. But bear in mind, this is principally a science oriented list, and is meant to be accessible to undergraduates – I left out books like Principia Mathematica (Newton) because it is really rather unreadable – and the Princeton Science Library (though awesome) is probably a bit too intense. Also, in the 30 minutes since I sent the email, I have already thought of several others I sort of, well, forgot:

That’s it for now…

What exactly is temperature? Ever wondered?

We take it for granted. We understand it. It is obvious what temperature is. Cold, warm, hot…obvious.

But how many of us have asked the next question: what is the real difference between a hot stone and a cold one? The answer is interesting and helps us to realise that measuring temperature is much trickier than we tend to suppose.

Over many hundreds of years, many clever people have devised lots of experiments to understand what temperature is, I hope in this article to round up the facts!

Temperature and Energy

For much of history, there were only a few sources of heat – the sun, fire, lava and of course the warmth of living creatures.

People were puzzled by what created it, but it was immediately obvious that it had one consistency – whenever it had the chance, it flowed – put something hot next to something cold, and the heat would flow.

Of course you could argue that it was the ‘cold’ that flowed (the other way), but there were no obvious sources of ‘cold’. While ice was clearly cold, it was not a sustainable ‘source’ of cold the way a fire was.

It was also noted that heat melted things – like fat or butter and that it make some liquids (like molasses) thinner. It could even boil water and make it ‘vanish’. The mechanisms for these were unknown and a source of fascination for early scientists.

Early experimenters noticed that gases would increase in volume upon heating, and that compressing gases would cause them to heat up. They also investigated other sources of heat, like friction, (rubbing your hands together).

It was the work with gas that led to the big breakthrough. Boyle and Hooke, as well as Edme Marriotte, working in the 17th century, realized that the temperature of a gas would increase consistently with pressure, and like-wise, decrease consistently with pressure. This sounds unremarkable, until you note that you can only decrease pressure so much…

Once you have a vacuum (no pressure), you should have ‘no temperature’. Thus their observations implied that there really was a limit to how cold things could get, and predicted it was around -275 Celsius. They were of course unable to cool anything that far simply by expanding it because heat always flows into cold things, so to achieve this you need much better insulation than they had available.

So they had a big clue in the search to understand what temperature is, but still no explanation.

It took until 1738 until another great scientist moved us forward. Daniel Bernoulli realised you could use Newton’s (relatively new) laws to derive Boyle’s temperature-pressure relationship. He basically asked: what if gas was made of a large number of very small billiard balls flying around crashing into everything? What if pressure was just the result of all these collisions? Using this theory he realised, for the first time I think, what temperature truly is.

Source: Wikimedia Commons

It turns out that his model equated temperature with the speed of the billiard balls. A hot gas only differs from a cold gas in the speed of the molecules flying around. Faster molecules crash with more momentum and thus impart more pressure. Squashing the gas into a smaller volume does not give them more speed, but means more collisions each second, so higher pressure.

This is a pretty serious finding. It basically says ‘there is no such thing as temperature’. There is only lots of little balls flying around, and their number and speed dictate the pressure they exert, and there is no ‘temperature’.

If we put a thermometer into the gas, what is it detecting then? Great question.

It turns out that solids are also made of lots of balls, except, instead of being free to fly around, they are trapped in a matrix. When a solid is exposed to a hot gas,  it is bombarded by fast flying atoms. When a solid atom is hit, instead of flying off, it starts to vibrate, like a ball constrained by a network of springs.

So the ‘temperature of a solid is also a measure of speed of motion, but rather than linear speed it’s a measure of the speed of vibration. This makes a lot of sense – as the solid gets hotter, the balls are going literally ‘ballistic’ and eventually have enough speed to break the shackles of the matrix (aka melting).

Source: Wikimedia Commons

So this model of heat as ‘movement’ not only explains how gases exert pressure, but also explains how heat flows (through molecular collisions) and why things melt or vaporise.

More importantly, it shows that temperature is really just a symptom of another, more familiar, sort of energy – movement (or kinetic) energy.

Energy is a whole story of its own, but we can see now how energy and temperature relate – and how we can use energy to make things hot and cold.

Making Things Hot

There are many easy ways to make things hot. Electricity is a very convenient tool for heating – it turns out that when electric current flows, the torrent of electrons cannot help but buffet the atoms in the wire, and as they are not free to fly away, they just vibrate ever faster, ‘heating’ up.

Another way to heat things is with fire. Fire is just a chemical reaction – many types of molecules (like methane, or alcohol) contain a lot of ‘tension’, that is to say, they are like loaded springs just waiting to go off. Other molecules (often oxygen)  hold the ‘key’ to unlocking the spring, and when the springs go off, as you can imagine, it is like a room full of mousetraps and ping-pong balls – and all that motion – means heat.

Making Things Cold

Manipulating energy flows to make things cold is much trickier.

One way it to just put the thing you want to cool in a cold environment – like the north pole. But what if you want to make something colder than its surroundings?

Well there is a way. We learned earlier that gases  get hot when compressed – it turns out they do the opposite when decompressed or ‘vented’. This is the principle that makes the spray from aerosol cans (deodorant, lighter fluid, etc) cold. So how can we use this? First we use a compressor to compress a gas (most any gas will do); in the process it will warm up, then you let it cool down by contacting it with ambient air (through a long thin copper tube, but keeping it compressed), then decompress it again – hey presto, it is cold! Pump this cold gas through another copper tube, inside a box, and it will cool the air in the box – and hey presto, you have a refrigerator.

Measuring Temperature

Before we had thermometers, temperature was generally estimated by touch.

However this is where temperature gets tricky. Because the temperature we feel, when we put our hand on the roof of a car is not really the temperature of the car, it’s really the measure of energy flow (into our hand), which relates to the temperature, but also relates to the conductivity of the car.

This is why hot metal feels hotter than hot wood, why cold metal feels colder than cold wood – the metal, if at a different temperature to your hand, is able to move more heat into you (or take more heat away) faster than wood can. Thus our sense of temperature is easily fooled.

The ‘wind-chill factor’ is another way we are fooled – we generally walk around with cloths on, and even without clothes we have some body hair – therefore, we usually carry a thin layer of air around with us that is nearly the same temperature as we are. This helps us when it is cold and when it is hot – however, when the wind blows it rips this layer up and supplies fresh air to our skin – making us feel the temperature more than usual. Also, because our skin can be damp, there can be evaporative effects which can actually cool you below the air temperature.

Scientists have long known that we cannot trust ourselves to measure temperature, so over the ages many tricks have been developed – can the object boil water? Can it freeze water? A long list of milestone temperatures was developed and essential knowledge for early scientists – until the development of the lowly thermometer.

It was noted that, like gases, solids and liquids also expand upon heating. This makes intuitive sense if you think of hot molecules as violently vibrating – they push one another away, or at least if the charge  (electric charge is what holds these things together) is spread just a little thinner, adjacent molecules will have slightly weaker bonds.

The expansion of liquids may only be very slight, and if you have a big volume of liquid in a cup, the height in the cup will change only very slightly, but if its in a bottle with a narrow neck, the small extra volume makes a bigger difference to the level. This principle is used in a thermometer – it’s just a bottle with a very narrow and long neck. The bigger the volume and the narrower the neck, the more sensitive the thermometer. Of course the glass also expands, so it is important to calibrate the thermometer – put it in ice water, mark the liquid level – then put it in boiling water and mark the new level. Then divide the distance between these marks into 100 divisions – and hey presto! you have a thermometer calibrated to the centi (hundred) grade (aka Celsius) scale. Now you know where that came from!

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So that is temperature explained in a nutshell.  If you enjoyed this article you may enjoy my related article on energy.

How to prove that space is curved…

Question: if you lived in flatland (a 2-d world), how could you tell if the land was curved in the third dimension?

Answer: geometry!

It turns out many of the mathematical rules we learned at school ‘fall apart’ if the working surface is curved. For example, can you draw a square on the surface of a sphere? No!

So can we use this insight to tell if our 3-d world is curved in a mysterious fourth dimension? Yes!

If we set off from earth, went in straight line for, say 1 light-year, then turned 90º, went 1 light-year, turned 90º again, and then did this yet again, you should have traced a perfect square, and be back exactly where you started. If you aren’t, something is amiss!

 

Now it turns out that it we do this, we will indeed discover an error; but why? And how do we know this?

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Newton told us that a massive object in motion will continue to travel in a straight line, unless acted upon by external forces. Some people think that Einstein overturned this insight, but he didn’t; indeed he extended it: he said that the force of gravity is not actually a force, and thus objects falling under gravity are actually going in straight lines! Indeed this makes sense, as anyone ‘falling’ does indeed not sense any acceleration, but rather feels ‘weightless’. Thus they are not actually accelerating, they are going straight – in curved space.

Now anyone who has thrown a ball can see this is absurd on the face of it, but Einstein was serious, and he is right, from a certain perspective. The ball is not going in a straight line through ‘regular’ space, but is going on a straight path in a 4-d construct called ‘space-time’. Likewise, he would argue that the planets are tracing straight lines around the sun; and indeed the ‘parabola’ of a baseball is actually not a parabola, but a very small part of the enormous ellipse that would be traced in the baseball could fall though the earth and go into ‘orbit’ §.

Anyway, Einstein’s model says that light travels in straight lines, but we have seen that light bends when it passes near to the sun (this can most easily be tested during an eclipse) – so… if one of the sides of your ‘perfect square’ were to pass near the sun, it would also be bent and if you followed the above rule to draw the square, you would not end up where you started.

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Physicists have grown used to Einstein’s model, and better tests for the flatness of space have been developed. For example, if you drew a circle on the surface of a sphere, the area would not equal Πr2, but would be less. Likewise, in 3-D space, we could plot a sphere and then measure the volume and if it did not equal 4/3Πr3, we would know something was amiss.

So physicists have looked at how light bends, and how the planets move, and found out, amazingly (but predicted by Einstein) that the error in this spherical volume calculation is directly proportional to the mass of matter within the sphere – proving that the warpage in space is proportional to (and thus caused by) ‘mass’.  Thus mass warps space.

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MC Escher: 'Grid'

But is space really warped in some ‘extra’ dimension?

Well, this is a good question. Maybe it is some extra ‘spacial type’ dimension, but you could also look at time as a fourth dimension, and argue that this space is not ‘curved’ at all, but rather that space and time simply vary in density in different locations. I personally like this way of looking at it, it eliminates the need for some vague ‘extra dimension’, and therefore swiftly removes the possibility that space could be ‘closed’ or fold back on itself in this extra spacial dimension. Occam’s razor thus prefers the ‘density’ model!

Footnotes:

§. In Wikipedia, they state that balls bounce in perfect parabolas, but note they also mention a ‘uniform’ gravitation field, and it is well to remember that the earth gravitational field is not uniform, but radial. Thus I stand by my assertion that missiles follow elliptical paths just like planets and comets. Of course, an ellipse is a close relative of both the parabola and the hyperbola, so this is not really that dramatic.

Did you know…

…that… Magenta Ain’t A Colour?

A nice bit of odd science from Liz Elliot.

It turns out that the block below is not a regular colour (wavelength of light), but a clever thing your brain has done, especially for you. Nice.

Magenta!

Of course, that is true for all colours, they are projections from our brains onto the world. The world itself has no colour, only common EM signatures we recognise and label with what we call ‘colour’. Gotta admire the brain, really.

Energy Explained in One Page

Ok, so we all want to be good to the environment. The first step to doing this, as is often the case – is to understand the main characters in the story – and possibly the biggest character in the story in Energy.

However, energy is such a very vague concept, so where do you go to learn more? Do you have to do a physics course?

I don’t think so, and to test my theory, I have tried to explain energy as briefly as I can in this post.

Energy 101

Energy is what makes the world go round. Literally. Every neuron that sparks in your brain, every electron that fires down a wire, every molecule burning in a fire, carries with it a sort of momentum that it passes on like a baton in a complex relay race. The batons are flooding in all directions all around us and across the universe – they are energy and we have learned how to harness them.

The actual word “Energy” is a much abused term nowadays – because energy is used to represent such a disparate range of phenomena from heat to light to speed to weight, and because it seems to be able to change forms so readily, it is cannon fodder for pseudo-scientific and spiritual interpretation. However, you will be pleased to hear that it actually has a very clear (and consistent) nature.

I like to think of energy being a bit like money – it is a sort of currency that can be traded. It takes on various forms (dollars/pounds/swiss francs) and can be eventually cashed in to achieve something. However, just like money, once spent, it does not vanish. It simply moves on a new chapter in its life and may be reused indefinitely.

§Energy currencies:{1}Matter is energy(see footnotes) {2} Radiation {3} Chemical energy {4} Thermal (heat) energy {5} Compression energy {6} Kinetic (movement) energy {7} Electrical energy

To illustrate the point, let’s follow a ‘unit of energy’ through a visit to planet Earth to see what I mean. The [number] shows every time it changes currency (see the key on the right).

The energy starts off tied up in hydrogen atoms in the sun [1]. Suddenly, due to the immense pressure and heat, the nuclei of several atoms react to form a brand new helium atom, and a burst of radiation[2] is released. The radiation smashes into other nearby atoms heating them up so hot [4] that they glow, sending light [2] off into space. Several minutes pass in silence before the light bursts through the atmosphere and plunges down to the rainforest hitting a leaf. In the leaf the burst of power smashes a molecule of carbon dioxide and helps free the carbon to make food for the plant [3]. The plant may be eaten (giving food ‘Calories’), or may fall to the ground and settle and age for millions of years turning perhaps to coal. That coal may be dug up and burned to give heat [4] in a power station, boiling water to supply compressed steam [5] that may drive a turbine [6] which may be used to generate electricity [7] which we may then use in our homes to heat/light/move/cook or perhaps to recharge our mobile phone [3]. That energy will then be used to transmit microwaves when you make a call [2] which will mostly dissipate into the environment heating it (very) slightly [4]. Eventually the warmed earth radiates [2] this excess of heat off into the void where perhaps it will have another life…

This short story is testament to an enormous quantity of learning by our species, but there are some clear exclusions to be read into the story:

  • Energy fields (auras) or the energy lines in the body that conduct the “chi” (or life force) of Asian medical tradition
  • Energy lines on the Earth (aka Ley lines)
  • Negative or positive energy (as in positive or negative “vibes”)

These energy currencies relate to theories and beliefs that science has been unable to verify and thus they have no known “exchange rate”. Asking how many light bulbs can you power with your Chi is thus a nonsensical question, whereas it would not be for any scientifically supported form of energy. And since energy flows account for all actions in the universe, not being exchangeable would be rather limiting.

Where exactly is Energy kept?

This may sound like s strange question, we know Energy is kept in batteries, petrol tanks and chocolate chip cookies. But the question is, where exactly is it stored in those things?

Energy is stored in several ways:

  • as movement – any mass moving has energy by virtue of the movement, which is called Kinetic Energy
  • as matter – Einstein figured out that matter is just a form of energy, and the exchange rate is amazing – 1g = 90,000,000,000,000,000 joules (from E=mc^2)
  • as tension in force fields

That last one sounds a bit cryptic, but actually most of the energy we use is in this form –  petrol, food, batteries and even a raised hammer all store energy in what are essentially compressed (or stretched springs).

What is a force field? Why on earth did I have to bring that up?

All of space (even the interstellar vacuum) is permeated by force fields. The one we all know best is gravity – we know that if we lift a weight, we have to exert effort and that effort is then stored in that weight and can be recovered later by dropping it on your foot.

Gravity is only one of several force fields known to science. Magnetic fields are very similar – it takes energy to pull a magnet off the fridge , and so it is actually an energy store when kept away from the fridge.

The next force field is that created by electric charge (the electric field). For many years this was though to be a field all on its own, but a chap called Maxwell realised that electric fields and magnetic fields are in some senses two sides of the same coin, so physicists now talk of ‘electromagnetic’ fields. It turns out that electric energy (such as that stored in a capacitor) consists of tensions in this field, much like a raised weight is a tension in a gravity field. Perhaps surprisingly, light (as well as radio waves, microwaves and x-rays) are also energy stored in fluctuations of an energy field.

Much chemical energy is also stored in electric fields – for example, most atoms consist of positively charged nuclei and negatively charged electrons, and the further apart they are kept, the more energy they hold, just liked raised weights. As an electron is allowed to get closer to the nucleus, energy is released (generally as radiation, such as light – thus hot things glow).

The least well known force field is the strong ‘nuclear’ force. This is the forces that holds the subatomic particles (protons) together in the nucleus of atoms. Since the protons are all positively charged, they should want to repel each other, but something is keeping them at bay, and so physicists have inferred this force field must exist. It turns out their theory holds water, because if you can drag these protons a little bit apart, they will suddenly fly off with gusto. The strong nuclear force turns out to be bloody strong, but only works over a tiny distance. It rarely affects us as we rarely store energy with this energy field.

Now we understand force fields we can look at how molecules (petrol, oxygen, chocolate) store energy. All molecules are made of atoms connected to one other via various ‘bonds’ and these bonds are like springs. Different types of molecules have different amount of tension in these bonds – it turns out coal molecules, created millions of years ago with energy from the sun, are crammed full of tense bonds that are dying to re-arrnage to more relaxed configurations, which is exactly what happens when we apply oxygen and the little heat to start the reaction.

The complexity of the tensions in molecules are perhaps the most amazing in nature, as it is their re-arrangements that fuel life as we know it.

What exactly is Heat then?

You may have noticed that I did not include heat as a form of energy store above. But surely hot things are an energy store?

Yes, they are, but heat is actually just a sort of illusion. We use heat as a catch all term to describe the kinetic energy of the molecules and atoms. If you have a bottle of air, the temperature of the air is a direct consequence of the average speed of the molecules of gas jetting around bashing into one another.

As you heat the air, you are actually just increasing the speed of particles. If you compress the air, you may not increase their speed, but you will have more particles in the same volume, which also ‘feels’ hotter.

Solids are a little different – the atoms and molecules in solids do not have the freedom to fly around, so instead, they vibrate. It is like each molecule is constrained by elastic bands pulling in all directions. If the molecule is still, it is cold, but if it is bouncing around like a pinball, then it has kinetic energy, and feels hotter.

You can see from this viewpoint, that to talk of the temperature of an atom, or of a vacuum, is meaningless, because temperature is a macroscopic property of matter. On the other hand, you could technically argue that a flying bullet is red hot because it has so much kinetic energy…

Is Energy Reusable?

We as a species, have learned how to tap into flows of energy to get them to do our bidding. So big question: Will we use it all up?

Scientists have found that energy is pretty much indestructable – it is never “used-up”, it merely flows from one form into another. The problem is thus not that we will run out, but that we might foolishly convert it all into some unusable form.

Electricity is an example of really useful energy – we have machines that convert electricity into almost anything, whereas heat is only useful if you are cold, and light is only useful if you are in the dark.

Engineers also talk about the quality (or grade) of energy. An engineer would always prefer 1 litre of water 70 degrees warmer than room temperature, than 70 litres of water 1 degree warmer, even though these contain roughly the same embodied energy. You can use the hot water to boil an egg, or make tea, or you could mix it with 69 litres of room temperature water to heat it all by 1 degree. It is more flexible.

Unfortunately, most of the machines we use, turn good energy (electricity, petrol, light) into bad energy (usually “low grade heat”).

Why is low grade heat so bad? It turns out we have no decent machine to convert low grade heat into other forms of energy. In fact we cannot technically convert any forms of heat into energy unless we have something cold to hand which we are also willing to warm up; our machines can thus only extract energy by using hot an cold things together. A steam engine relies just as much on the environment that cools and condenses water vapour as it does on the coal its belly. Power stations rely on their cooling towers as much as their furnaces. It turns out that all our heat machines are stuck in this trap.

So, in summary, heat itself is not useful – it is temperature differences that we know how to harness, and the bigger the better.

This picture of energy lets us think differently about how we interact with energy. We have learned a few key facts:

  1. Energy is not destroyed, and cannot be totally used up – this should give us hope
  2. Energy is harnessed to do our dirty work, but tends to end up stuck in some ‘hard to use’ form

So all we need to do to save ourselves is:

  1. Re-use the same energy over and over
  2. by finding some way to extract energy from low grade heat

Alas, this is a harder nut to crack than fission power, so I am not holding my breath. It turns out that there is another annoying universal law that says that every time energy flows, it will somehow become less useful, like water running downhill. This is because energy can only flow one way: from something hot to something cold – thus once something hot and something cold meet and the temperature evens out, you have forever lost the useful energy you had.

It is as if we had a mountain range and were using avalanches to drive our engines. Not only will our mountains get shorter over time but our valleys will fill up too, and soon we will live on a flat plane and our engines will be silent.

The Big Picture

So the useful energy in the universe is being used up. Should we worry?

Yes and no.

Yes, you should worry because locally we are running out of easy sources of energy and will now have to start using sustainable ones. If we do not ramp up fast enough we will have catastrophic shortages.

No, should should no worry that we will run out, because there are sustainable sources – the sun pumps out so much more than we use, it is virtually limitless.

Oh, and yes again – because burning everything is messing up the chemistry of the atmosphere, which is also likely to cause catastrophe. Good news is that the solution to this is the same – most renewable energy sources do not have this unhappy side effect.

Oh, and in the really long term, yes we should worry again. All the energy in the universe will eventually convert to heat, and the heat will probably spread evenly throughout the universe, and even though all the energy will still be present and accounted for, it would be impossible to use and the universe would basically stop. Pretty dismal, but this is what many physicists believe: we all exist in the eddy currents of heat flows as the universe gradually heads for a luke-warm, and dead, equilibrium.

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Ok, so it was longer than a page, so sue me. If you liked this article, my first in a series on energy conservation, you might like my series on efficient motoring.

Please leave a comment, I seem to have very clued-up readers and always love know what you think!

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§ Footnotes:

[1] Matter is energy according the Einstein and the quantity relates to mass according to E=mc^2 (c is a constant equal to the speed of light).

[2] Radiation (like sunlight) is a flow of energy, and energy content relates the frequency according to E=hf (h is the Planck constant).

[3] Chemical energy – the most complex energy, a mixture of different tensions in nuclear and electromagnetic force fields.

[4] Thermal (heat) energy- this is really just a sneaky form of kinetic energy [6 below] – small particles moving and vibrating fast are sensed by us as heat.

[5] Compression (or tension) energy – while compressed air is again a sneaky form of kinetic energy [6], a compressed spring is different – it’s energy is more like chemical energy and is stored by creating tension in the force fields present in nature (gravity, electromagnetism and nuclear forces).

[6] Kinetic (movement) energy

[7] Electrical energy – this energy, like a compressed spring, is stored as stress in force fields, in this case electromagnetic force-fields.

Does your company need a corporate scientist?

Question: what is the point of having a scientific advisor?

We know the scientist type – they are pedantic, idealistic, inflexible – and socially challenged.

They are generally unable to do business in ‘the real world’. So why would you want one on the team?

We all know that business has some hard rules – the machines need to work and the numbers need to add up – but it is also an art – it is about people, about relationships, deals, loyalties, reputations. It takes care and passion. It is often irrational and is generally completely unpredictable.

So if it cannot be modelled and reduced to equations, why would you want an irritating pedant on the team?

Because in a complex world, the truth is worth its weight in gold.

A scientist’s job, is to use his or her training to filter out emotions, wishful thinking, bias and noise and identify what is true.

Just as every salesperson has their patter, every ceo will have their ‘summary’ for the board – and what they say will be wilfully spun. However, so long as they themselves know the basic truth, they will still be able to act wisely. They will also be able to maintain credibility pinning their spin on little nuggets of purest ‘truth’.

A world without a constant return to rational analysis will eventually wind up so twisted (the proverbial tangled web) that we will get entire businesses built on air.

Ok, so maybe we need someone to provide the boss with the unvarnished truth. What they then do with it then, well that’s business!

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Aside for accountants: To be fair, accountants are also supposed to do this, but I would argue that only a true scientist will (probably through a mental fault) put truth first. Note that I am not saying scientists are more honest than other people – they lie and cheat too, it’s a desire to find the truth that I’m talking out, which is no guarantee of a desire to speak it.

Overlapping Magisteria

Those who say science and religion are mutually exclusive are working from the philosophical premise that there can be something outside of nature.

Those who claim that religion can be scientifically investigated, come from the philosophical premise that there is nothing outside of nature.

As neither position is superior one cannot use logic to assign greater truth.

However, the claim that there is anything beyond nature (i.e. supernatural) is the more extraordinary claim, and thus carries with it the onus to justify and explain how to reach this conclusion.


The futility of being outside of nature:

If religion is truly outside of nature it can have no measurable effect on it. If it has no measurable effect then, even if existant, it would be fair to say it couldn’t be detected by science – but then neither could it be detected by the clergy.

Thus in a non-overlapping model, the benefits of a benevolent God, such as good crops, good weather, good luck, healing or charity are impossible, as they are generally detectable.

I guess you could argue that God goes to the trouble to disguise the causes for His blessings, but why is he so afraid to show it was the result of your good faith? This argument gets a little stretched once the solutions to that are proposed. It is similar to the argument that God planted the fossils in the order of their evolutionary development to fool us into thinking that life evolved…

What exactly is ‘science’?

I used to think science was the practice of the scientific method; i.e. you propose a hypothesis, you develop a test of the hypothesis, execute it and prove the hypothesis.

That worked for me until the end of high school.

At university, I was a true nerd. I read all my textbooks cover to cover (mainly because as I was too shy for girls and too poor for booze). During this time, the definition above started to fail. So much of the science was maths, statistics, observation, pattern recognition, logic and quite a bit of rote learning. Not all of it fitted into my definition of science. I became a fan of a new definition: science is the study of the nature of reality .

But then I did post-grad, and I realised that not much in science is ‘proven’ (I guess this is the point of post grad study). Evolution, for example, is not proven. That the sun revolves around the earth is not ‘proven’. I discovered that the only things that could be proven were ‘ideas’ about ‘other ideas’. Bear with me on this one.

Let us say we define the number system – this is an ‘idea’ or conceptual construction. Within this construction we can ‘prove’ that one and one is two. Because we ‘made’ the system, with rules, then we can make factual and true statements about it. We can’t do this about the real world – we cannot say anything with absolute certainly because we rely on flaky inputs like our own highly fallible perception.

It’s like that old chestnut: how can you be sure you are not living in a giant simulation? Of course you can argue that it is pretty unlikely and I would agree, and right there we have a clue to a better definition of science.

It turns out that much of modern science deals in ‘likelihood’ and ‘probability’ rather than proof and certainty. For example, we can say that the theory of evolution is very likely to be more-or-less right, as there is a lot of corroborating evidence. Science cannot be run like a law court – where the prosecution only need to reach a threshold of reasonable doubt to ‘prove’ someone guilty.

Aside for nerds: Science says you can use logic to prove things absolutely, but logic only works with ideas, and there is a breakdown between ideas and reality, so one can never prove things in reality. So it is thoroughly wrong for a court to say that someone has been proven guilty. The courts use this language as a convenience, to “draw a line under” a case as they have not found a moral way to dole out punishments based on probabilities. Imagine a world in which a murder suspect gets a 5 year sentence because the was a 20% chance he was guilty! Sports referees often operate in this decisive way, perhaps because it saves a lot of arguing!

Anyway, good science cannot just give up and say once there is consensus something passes from theory to fact. This is sloppy. We have to keep our options open – forever.

Think for example of Newton’s Laws of Motion. They are called ‘Laws’ because the scientific community had so much faith in them they passed from theory (or a proposed model) to accepted fact. But they were then found wrong. Strange that we persist in calling them laws!

It took Einstein’s courage (and open mindedness) to try out theories that dispensed with a key plank of the laws – that time was utterly inflexible and completely constant and reliable.

So it is that the canon of scientific knowledge has become a complex web of evidence and theories that attempt to ‘best fit’ the evidence.

Alas, there are still many propositions that many so-called scientists would claim are fact or at least ‘above reproach’. Evolution is attacked (rather pathetically), but the defenders would do well to take care before they call it ‘fact’. It is not fact, it is a superbly good explanation for the evidence, which has yet to fail a test of its predictions. So it is very very likely to be right, but it cannot be said to be fact.

This is not just a point of pedantry (though I am a bit of a pedant) – it is critical to keep this in mind as it is the key to improving our model.

Two great examples of models people forget are still in flux…

1) The big bang theory

2) Quantum theory

I will not go into global warming here though it is tempting. That is one where it doesn’t even matter if it is fact, because game theory tells you that either way, we better stop making CO2 urgently.

Back to the big bang.

I heard on the Skeptic’s Guide podcast today about an NSF questionnaire that quizzed people about whether they believed the universe was started with a massive explosion, and they tried to paint the picture that if you didn’t believe that, then you were ignorant of science. This annoyed me, because the big bang theory is now too often spoken of as if it were fact. Yes, the theory contributes viable explanations for red-shifted pulsars, background radiation, etc, etc, but people are quick to forget that it is an extrapolation relying on a fairly tall pile of suppositions.

I am not saying it is wrong, all I am saying is that it would be crazy to stop exploring other possibilities at this point.

You get a feeling for the sort of doubts you should have from the following thought experiment:

Imagine you are a photon born in the big bang. You have no mass, so you cannot help but travel at ‘light speed’. But being an obedient photon, you obey the contractions in the Lorentz equations to the letter, and time thus cannot pass for you. However, you are minding your own business one day when suddenly you zoom down toward planet earth and head straight into a big radiotelescope. Scientists analyse you and declare that you are background radiation dating from the big bang and that you have been travelling for over 13 billion years (they know this because they can backtrack the expansion of the universe). Only trouble is, that for you, no time has passed, so for you, the universe is still new. Who is right? What about a particle that was travelling at 0.999 x the speed of light since the big bang? For it, the universe is some other intermediate age. So how old is the universe, really?

This reminds us of the fundamental proposition of relatively – time is like a gooey compressible stretchable mess, and so is space, so the distance across the universe may be 13.5 billion light years, or it might be a micron (how it felt to the photon). It all depends on your perspective. It is much like the statement that the sun does not revolve around the earth and that it is the other way around. No! The sun does revolve a round the earth. You can see it clearly does. From our perspective at least.

Now, quantum theory.

Where do I start? String theory? Entanglement? Please.

The study of forces, particles, EM radiation and the like is the most exciting part of science. But being so complex, so mysterious, so weird and counter intuitive, it is super vulnerable to abuse.

Most people have no idea how to judge the merits of quantum theories. Physicists are so deep in there, they have little time (or desire or capability) to explain themselves. They also love the mystique.

I do not want to ingratiate myself with physicists, so I will add that the vast majority have complete integrity. They do want to understand and then share. However, I have been working in the field for long enough to know that there are weaknesses, holes and downright contradictions in the modern theory that are often underplayed. In fact these weaknesses are what make the field so attractive to people like me, but is also a dirty little secret.

The fact is that the three forces (weak nuclear, strong nuclear and magnetic) have not been explained anything like as well as gravity has (by relativity). And don’t get me started on quantum gravity.

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Anyway, thinking about all these issues, I concluded that science was (definition #3) the grand (platonic) model we are building of reality, ever evolving to best fit our observations.

My man, Plato

That works well for me. However, I recently came across a totally different definition for science:

# 4) “Science is a tool to help make the subjective objective.”

OK I paraphrased it to make it more snappy. It was really a discussion about how science was developed to overcome the fallibility of the human mind. Examples of weaknesses it needs to overcome are:

  1. The way our perception is filtered by preconceptions
  2. How we see pattern where there is none
  3. How we select evidence to match our opinion (confirmation bias)
  4. How we  read too much into anecdotal evidence
  5. etc etc.

I could go on. So ‘science’ is the collection of tricks we use to overcome our weaknesses.

I like this definition. We are all going about, and in our heads we are building our model of the world… and its time for an audit!