Category Archives: The scientific method

Another way to think about Space-Time: A fresh start…

I have been kept away from writing on this for a few years, due to life – three kids, crazy job, lot’s of travel, yada yada. But that was true before so that’s a bullshit excuse.

The real reason I kept away because I was discouraged.

I had got stuck in my progress of understanding space-time.

But today I got a wake-up call…


I read a book excerpt (on Gizmodo) of ‘Spooky Action at a Distance’ bu George Musser just published last week.

And right there, in plain English, it was: “If you agree that the fundamental level of physics is not local, everything is natural, because these two particles which are far apart from each other explore the same fundamental nonlocal level. For them, time and space don’t matter.” A quote of Micheal Heller.

Damn. People thinking about quantum entanglement decided that if we accept distant entanglement was indeed ‘real’, as we accepted the speed limit on light is ‘real’, that space itself would adapt to avoid a paradox.


So what?

Well, in my own work I had decided that exactly the same assumption could be used to explain away the weird interference in the double-slit experiment.

My approach was this:

If we take the Lorentz Transformation to calculate the geometry of the double slit, we see that from the perspective of the single photon, the whole journey is compressed into a single spot. And under such conditions, interference between the ‘possible paths’ is no longer a contradiction.

It also hints tantalizingly that the wave nature of light is a sort of artifact of trying to cross section what is essentially a point event.

I am therefore very grateful to George Musser, because he will allow me to pick up this thread and see where it leads.


I like to start by imagining I am a photon, leaving from, say, my nose, and heading away from earth across the galaxy, eventually terminating somewhere, let’s say on a far-off star – being absorbed as an electron there leaps up to a higher orbital.

From the photon’s own perspective, if that’s a possible perspective to have, time has not progressed – this means it leaves, travels and arrives at once. This means that even as the photon is waiting to leave an atom on my nose, there is a sort of connection with another atom, far away across the galaxy, which is waiting to accept the photon, and then click, all of that distance disappears, it’s all a single point in space, and the photon relocates, somehow without even having to move. My nose and the stars are somehow momentarily at one. Spooky…

This started as a fancy, but I can’t seem to break it!

For example – the approach also seems to have something to say about energy quantisation…

The issue there is that electrons should fall to the atomic nucleus, but don’t – this is because they can’t find an outlet for ‘that particular quantity’ of energy.

Now, with the idea that space and distance are illusory, we can look at every photon emission as paired with an ‘acceptance’ somewhere else. So far we’ve assumed these are unrelated events, but now we see they must be the same event – so it seems natural that these events require some degree of serendipity to occur. Not just any atom can absorb just any photon…

It strikes me we could test this thinking, how can we do it?

Can we send photons that really have no inevitable target? Seems like we could, but the maths is telling me no…


PS See my first public post about this subject from 2011 here.

The speed of evolution – revisited…

I have been keeping my eye on the evidence that ‘life experience’ can be passed on in your genes.DNA

It has been proposed many times as a mechanism of evolution, and indeed was considered likely before the concept of ‘selection’ was understood. It’s attractive because saying that ‘survival’ is the one and only way to adding value to the genes seems, well, wasteful.

Surely, you’d think that a fear of snakes based purely on the idea that people who were not afraid of snakes were ‘taken out’ of the gene pool by snakes, is less efficient than a mechanism that captures experience – that snake killed my dog, I should avoid snakes, and so should my kids…

However, once DNA was understood and shown to be dense with what seemed to be all information that could ever be needed, dissent waned to an all time low. The mechanisms of DNA were pretty clear – your DNA was set at birth and while it might mutate a little randomly, had no way to ‘learn’ from your life before being combined with a partner’s to create offspring. The case seemed pretty settled.

There remained niggles though. I worried about the speed of evolution as we have so very much to learn and so little time to evolve! So I looked for ways evolution could amp up its power. It seemed to me that nature, so darn clever at self-optimisation would make improvements to our design based on non-fatal experience, or indeed passive observation.

Others similarly concerned continued, often in the face of deep scepticism, to study what is called epigenetics, the science of heritance not coded by DNA – and thus having the potential to be edited during our lives.

I first heard about it around 10 years ago when media reported that the actual DNA sequence was not the only way info could be stored in cells – in theory the histones present can affect how the DNA ‘works’ (how genes are ‘expressed’) and their presence could thus change the characteristics of any lifeform coded therein. The type and number of histones may be few (relative to the number of base pairs in DNA) however, the many locations and orientations they can take create a fair number of possible combinations and permutations.

When I heard about this theory, I was put into a state of high curiosity. On the one hand, it was a little blasphemous, but on the other hand tantalising. If nature could find a way to combine the power of selection with the potential benefits of life experience, we could get much faster and more effective evolution.

My curiosity was soon rewarded with another possible mechanism for smuggling info to the next generation. DNA methylation – the idea is that DNA can host little ‘attachments’ in certain places. These may be temporary, and reversible, but they have now been clearly shown to alter how the DNA expresses itself.

On the face of it, the evidence that DNA expression is environment dependent is rather strong, but the idea that the environment around the DNA coil actually contains consistent and persistent intelligence picked up during our lives is much harder to prove.

And so teams have been beavering away trying to get to the bottom of this, and this week one such group has fresh news for us. A Nature Neuroscience paper has tested the theory in a rather clever way.

lab miceThey started by teaching some mice a new fact (that a certain smell would be associated with trauma) and then later, tested their kids. Lo and behold the kids whose parents had been taught fared significantly better in the test than untrained, unrelated mice.

This may sound a little trivial, but you must remember that the current ‘popular’ understanding of genes is that they only gain intelligence by surviving – or more precisely they shed stupidity by dying. However, here we are seeing information pass between generations without the need for anyone to die.

Furthermore, because of the carefully selected lesson taught to these mice, the researchers were actually able to see that a specific part of the DNA, while not different in design was nevertheless more active.

Now, I do not know enough about DNA to double-check this claim, but you can rest assured others will – because that’s what journals are for – and in this case the implications are huge.


Like what, you ask?

Well, off the top of my head, it means that much of what we do between birth and reproduction will affect all our descendents – this undermines the idea that one’s body is one’s own to do with as one pleases.

It also indicates that there is potential for us to deliberately control the expression of our DNA, allowing us to do some genetic engineering without actually changing the DNA sequence.

More importantly, and more controversially, it would mean natural selection would not need to explain all the marvellous diversity we see around us on its own.

It remains to be seen what proportion of our ‘design’ is coded for outside the DNA, or indeed how much this mechanism can improve or speed up evolution, however I for one hope it works out to be right and that mother nature has indeed figured out how to seriously boost the power of selection.

Negative pressure: impossible surely!!?

two_tall_treesI read some comments on Scientific American today that instantly made my blood boil. Or cavitate at least.

It was an explanation of how tall trees get water right up top. No I never thought about that before either.

water-boreholeAnyhow, anyone who’s drilled a borehole knows you can only suck water up 33 ft before you get a vacuum forming, water boiling and general pumping failure. Hence the need to put a pump at the bottom of a deep borehole.

Now, I had always thought capillary action was what sucked water up plants, handily bypassing this issue, and there, right in the comments, it was asserted that this was a ‘common misconception’…

What, me wrong!? Never!

After the shock, I did what a good scientist is supposed to do, fighting the desire to simply namecall, I watched her darn video.

I remained skeptical. Very skeptical. I again overcame desires to write rude comments in youtube and went a read up on it properly…


Ok, so it turns out that there is some sort of truth to it: indeed some clever people believe water can be ‘sucked’ to the top of tall trees, which does indeed require negative pressure.

So I ask, why won’t the water boil? Boiling-Water

Because, they say, it’s ‘meta-stable’. Like super-cooled water, or superheated water, water can supposed go to ‘tension’ without boiling if only you can prevent that initial bubble forming. Simple!

A little more thinking and internal wrangling, and I slowly conceded it just might be. Yes, ok, negative pressure is not really all that radical, it is essentially tension. It’s common in solids, it’s just the idea that water can be ‘tense’ that is difficult to get one’s head around.

So, the process had begun; I started to consider that maybe I was wrong. It’s not pleasant folks, and I am not trying to beat my own drum, I am sure there are plenty of other times when I’ve failed this test, it was just interesting because here I think I passed it…

Anyway, back to the point. Alas, I then read even more deeply, that though I find myself agreeing that water can indeed be under tension, and that sort of does mean negative pressure, I’ve yet to be convinced that ‘wicking’ it not at least involved in tree sustenance. Anyone who has dropped a dry cloth in water knows the water climbs into the fabric.

Furthermore, if there was negative pressure in the tree’s ‘pipes’ why wouldn’t they collapse?

It took deeper digging, but now all my cognitive dissonance is resolved, and I feel just fine by closing my investigation with this makeshift conclusion: that while trees do suck water up (via transpiration and the pull of surface tension in narrow openings) the pressures needed are not too crazy BECAUSE OF THOSE GOOL OL’ WICKING EFFECTS!!

Yup, I have to conclude that the attraction of the fluid for the xylem walls helps ‘keep the water up’ and thus preventing it from pulling too hard on the water above it.

It turns out this is what many others think [great minds for sure], and some [’nuff respect] took the steps of building a pressure probe small enough to poke into a plant’s pipework. What they found supports my newly cherished (but alas already 120-year-old) Cohesion-Tension theory of tree hydration.

In other words, while wicking (capillary action) is not a sole actor, it is there in a critical supporting role. Aaah that’s better, as you can see I wasn’t totally wrong 😉

PS. On the other hand, negative pressures seem to be a new and reproducible fact for us to worry about!

Requirements for Promoting a New Scientific Theory

I have been reading some pretty strange stuff about Gravity recently. It seems there are some pretty odd folk out there who have taken thinking about physics to a new, possibly unhealthy, level.

Gravity: It's the Law

Basically, they are crackpots. Well I guess it’s a slippery slope – one day you wonder why the earth is sucking down on you, the next you decide to spend some time on the knotty question. Soon enough you think you’ve got it, it is clearly that the earth is absorbing space which is constantly rushing down around us dragging us with it. Or similar.

So yes, its true, Einstein did not ‘solve’ Gravity, and there is still fame and fortune to be had in thinking about gravity, so this is the example I shall use today.

The trouble with Gravity is that Einstein’s explanation is just so cool! He explained that mass warps space and that the feeling of being pulled is simply a side effect of being in warped space. It sounds so outlandish, but also so simple, that it has clearly encouraged many ‘interesting’ people to have a crack at doing a better job themselves.

So, as a service to all those wannabe physics icons, I offer today a service, in the form of a checklist – what hoops will your new scientific theory have to jump through to get my attention, and that of the so-called ivory tower elite in the scientific community?

Requirement 1: Your theory needs to be well presented

presentation counts!Yes, it may sound elitist to say, but your documentation/website/paper/video should have good grammar. Yes, yes, one should not use the quality of one’s english to judge the quality of one’s theory, and I know prejudice is hard to overcome, but this is not my point. My point is that in order to understand a complicated thing like a physics theory it needs to be unambiguous. It needs to be clear. It needs to use the same jargon the so called ‘elite’ community uses. Invented acronyms, especially those with your own initials in them, are out.

Requirement 2: Your proposal needs to be respectful

Image courtesy of Wikimedia Commons

Image courtesy of Wikimedia Commons

Again, this is not about making you bow to your superiors in the academic world. Indeed in the case of Gravity, the physics community is one of the most humble out there. While I agree academia is up it’s arse most of the time, this is about convincing the reader that you know your stuff. In order to do that, you need to show that you know ‘their stuff’ too. If you have headings like “Einstein’s Big Mistake” it is a bit like saying to the reader ‘you are all FOOLS!’ and cackling madly. Don’t do it!

Respect also means you need to answer questions ‘properly’. That means clearly, fully, and in the common language of the community. You cannot say “its the responsibility of the community to test your theory”. This is a great way to piss people right off. It is your responsibility to make them want to. This usually means dealing with their doubts head-on, and if you can do that, I promise you they will then want to know more.

Requirement 3: You need to develop credibility

Sorry, as you can see we have yet to consider the actual merit of the theory itself. I wish it were not so, but we are humans first and scientists second. We cannot focus our thoughts on a theory if we doubt the payback. And if you say that aliens came and told you the scientific theory, then people are unlikely to keep listening, unless, perhaps they’re from Hollywood.

But seriously, credibility is the hidden currency of the world, it opens doors, bends ears and gets funds. It takes professionals decades to build and it is really rather naive to waltz into a specialism and expect everyone to drop their tools and listen to you.

That said, the science world is full of incomers, it is not a closed shop as some would you believe. If you follow requirements 1 and 2, and are persistent (and your theory actually holds water) then you are very likely to succeed.

Penrose_triangleRequirement 4: Your theory needs to be consistent

I have seen some pretty strange stuff proposed. Gravity is a manifestation of the flow of information, or the speed of light is determined by a planet’s density. Find your own at Let’s look at this peach as an example:

This exhibit is great example of how not to go about promoting your theory. “Monumental   Scientific   Discovery  !” it screams across the top, then the first claim is this:

1) The Acceleration of earth’s Gravity x earth orbit Time (exact lunar year) = the Velocity of Light.
(9.80175174 m/s2 x 30,585,600 s = 299,792,458 m/s)

Now this is rather remarkable. Can it really be that you can calculate the speed of light to 9 significant figures from just the earth’s gravitational acceleration and the length of a year? Intuitively I suspect you could (eventually), but then I started to think, well, what if the earth was irregularly shaped? The gravitational constant is actually not all that consistent depending on where you are either. So I checked, then I noticed he said ‘lunar year’. What? Why? What is a lunar year? Then I calculated that the time he used was 354 days, which isn’t even a lunar year. Add to that that he gives the acceleration of gravity on earth to 9-figures despite the fact that nobody knows it that well (like I said it is location dependent). Does he do the same test for other planets? No. Well what if they have no moon!

So, 0/4 for on our checklist for!

Requirement 5: The theory needs to be be consistent with well-known observationsevidence

Now if your theory has got past requirements 1-4 , well done to you, you will be welcome to join my table any time. Now is when you may need some more help.

Once a theory is consistent with itself, it now needs to agree with what we see around us. It needs to explain apples falling, moons orbiting, light bending and time dilating. This is the hardest part.

It cannot leave any out, or predict something contrary to the facts. It cannot be vague or wishy-washy. It needs the type of certainty we only get from the application of formal logic – and that old chestnut – mathematics.

No you cannot get away without it, there is no substitute for an equation. Equations derived using logic take all the emotion out of a debate. And they set you up perfectly for requirement #5.

crystal-ballRequirement 6: The theory needs to make testable predictions

If your theory has got past the 5 above, very nice job, I hope to meet you one day.

We are all set, we have a hypothesis and we can’t break it. It has been passed to others, some dismiss it, others are not so sure. How do you create consensus?

Simple, make an impressive prediction, and then test that.

Einsteins field equations for example, boldly provide a ‘shape’ of space (spacetime actually) for any given distribution of mass. With that shape in hand you should then be able to predict the path of light beams past stars or galaxies. These equation claimed to replace Newton’s simple inverse square law, but include the effects of time which creates strange effects (like frame dragging), which, importantly could be, and were, tested.

The beauty of these equations, derived via logical inference from how the speed of light seems invariate, and now proven many times, is that they moved physics forward. Rather than asking, ‘what is gravity’, the question is now ‘why does mass warp space’. It’s a better question because answering it will probably have implications far beyond gravity – it will inform cosmology and quantum theory too.


So if you are thinking of sharing with the world at last your immensely important insights, and want to be listened to, please remember my advice when you are famous and put in a good word for me in Stockholm. But please, if, when trying to explain yourself, and are finding it tough, please please consider the possibility that you are just plain wrong…


Jarrod Hart is a practicing scientist, and wrote this to shamelessly enhance his  reputation in case he ever needs to peddle you a strange theory.

Further reading:

Exceeding the Speed-Of-Light Explained Simply (and the Quantum riddle solved at no extra cost)

It has recently been in the news that some particle may have exceeded the legal speed limit for all things : 299,792,458 metres per second.

Of course, this will probably turn out to be a bad sum somewhere or perhaps waves ganging up, but the whole hubbub has raised my hackles, and here’s why.

Because Albert Einstein at no time said what they say he said (see here for example). They misunderstand relativity! Things can move at any speed we want, and I will try to explain the fuss now.

So let’s get to it!


First, we have to consider the way space warps when we move.

The problems started when people realised that light always seems to have the same speed, regardless of the speed you were moving when you saw it. This seems to be a contradiction, because surely if you fly into the light ever faster, it will pass you ever faster?

Well the tests were pretty clear, this does not happen. The speed is always c.

For several years, people were unsure why – until they were told by Einstein in 1905. In the meantime, another ponderer of the problem (Lorentz) decided to write down the maths that are required to square the circle.

The so-called Lorentz equations show, unequivocally, that space and/or time need to warp in order for relative speeds of c not to be exceeded, even when two items are going very close to c in opposite directions to one another.

So something needed to give, and it was space and time!

So, newsflash! it was not Einstein that first published on space and time warping. His contribution (along with Henri Poincaré and a few others) was to explain how and why. His special theory showed that because there is no ‘preferred’ frame of reference, a speed limit on light was inevitable. The term ‘relativity’ come from this – basically he said, if everything is relative, nothing can be fixed.


Ok, so we have some nice observations that nothing seems to go faster than the speed of light  – and we have a nice maths model that allows it. So why do I persist in saying things can go faster than the speed of light?

Let me show you…

There is a critical difference between ‘going’ faster than light and being ‘seen to be going’ faster than the speed of light, and that is where I am going with this.

So lets take this apart by asking how we actually define speed.

If a particle leaves point a and then gets to point b, we can divide the distance by the time taken and get the mean speed (or velocity to be pedantic).

The issue with relativistic speeds are that the clock cannot be in both point a and point b. So we need to do some fancy footwork with the maths to use one or other of the clocks. So far so good. This method will indeed never get a result > c.

The nature of space forbids it – if the Lorentz transformations that work so well are to be taken at face value, then for something to exceed c by this method of measurement, is much the same as a number exceeding infinity.

So all is still well. Until you ask, what about if the clock is the thing that travelled from a to b?

In this case, the transformations cancel! The faster the movement, the slower time goes for the clock, and you will see its ticks slow down, thus allowing its speed to exceed c.

The clock will cover the distance and appear to have tavelled at c on your own (stationary) clock, but the travelling clock will have ticked fewer times!

If you divide the distance by the time on the travelling clock, you see a speed that perfectly matches what you would expect should no limit apply. Indeed, the energy required to create the movement matches that expected from simple Newtonian mechanics.

The key point here is that while the clock travelled, the reader of the clock did not. If you do choose to travel with the clock, you will see it tick at normal speed, and see the limit apply – but see the rest of the universe magically shrink to make it so.

Some have argued that I am not comparing apples with apples, and that by using an observer in a different frame to the clock I am invalidating the logic.

To those who say that, I have to admit this is not done lightly. I have grown more confident that this inference is valid by considering questions such as the twin paradox over and over.

The twin paradox describes how one twin who travels somewhere at high speed and then returns will age less than his (or her) stationary twin.

Now if we consider a  trip to Proxima Centauri (our nearest neighbour) the transformations clearly show that if humans could bear the acceleration required (we can’t) and if we had the means to get to, say, 0.99c for most of the trip, that yes, the round-trip would take over 8 years and no laws would be broken. However the travellers themselves will experience time 7 times slower (7.089 to be precise). Thus they will have aged less than 8 years. So, once they get home and back-calculate their actual personal speed, it will exceed all the live measurements.

This has bothered me endlessly. Although taken for granted in some sci-fi books (the Enders Game saga for example) this clear ‘breakage of the c-limit’ is not discussed openly anywhere.

Still uncertain why people were ignoring this, I read a lot (fun tomes like this one) learned more maths (Riemann rules!) and also started to look at the wider implications of the assertion.

On the one hand, the implications are not dramatic, because instant interstellar communication is still clearly excluded, but that whole issue of needing a 4 years flight to get to Proxima Centauri is just wrong. If we can get closer to c we can indeed go very far into the universe, although our life stories will be strangely punctuated, just as in the Ender books.

But what about the implications for the other big festering boil on the body of theories that is physics today – quantum theory?

Well, if one is bold enough to assert that it is only measurement that is kept below c and not ‘local reality’, then one can allow for infinite speed.

In this scenario, we are saying measurement is simply mapping reality through a sort of hyperbolic lense such that infinity resembles a limit. Modelling space with hyperbolic geometry is really not as unreasonable as all that, I don’t know why we are so hung up on Euclid.

With infinite speed at our disposal, things get really interesting.

We get things like photons arriving at their destination the same tme they leave their source. Crazy of course… but is it?

Have we not heard physicists ask – how is it the photon ‘knows’ which slit is blocked in the famous double slit experiment? It knows because it was  spread out in space all the way from it’s source to it’s final point of absorption.

If you hate infinities and want to stick with Lorentz, you can equally argue that, for the photon, going exactly at c, time would stand still. Either way, the photon feels like it is everywhere en route at once.

If the photon is indeed smeared out, it probably can interfere with itself. Furthermore, it is fitting that what we see is a ‘wave’ when we try to ‘measure’ this thing.

A wave pattern is the sort of thing I would expect to see when cross sectioning something spread in time and space.

Please tell me I’m wrong so I can get back to worrying about something useful. No, don’t tell me – show me – please! 😉

Confirmation bias: confirmed as bias.

I have this theory that ‘confirmation bias’ is a load of BS, so I looked on the net and found, after careful search, some people who clearly agree with me. Most don’t, but they must be idiots.


Air Fresheners Exposed!

Ok, so I know its not a conspiracy to take over the world, but my inner nerd has been provoked.

Have you ever wondered how air fresheners work?

Let’s take a sceptical look.


This cool pic is from

I’d love to think that AirWick / Glade / {insert preferred brand here} consist of an army of nano-bots that round up and deport any molecules without the right paperwork.

Although we aren’t there yet, it’s actually not too far from the truth!

Although many cheap deodorisers do simply mask the truth by overpowering our senses, I really like to give credit where credit is due, so I am happy to disclose that there are indeed certain substances that can detain odours – such as zeolites and silica gels, and there are also organic molecules that will react with a wide array or hydrocarbons rendering them odourless. These ideas are in fact used by several big brands today.


But that’s not the whole story, is it?

No, because none of that really means the substance (or it’s source) is ‘gone’; all they have done is disabled our ability to detect all that foreign matter around us!

The last time I looked, our sense of smell, just like our sight and hearing, was there to help us survive – to detect when there is something unsavoury in the vicinity and force us to deal with it. If your bed or sofa stinks, you should probably take it outside and try to remove to 5 lbs of skins flakes and  other sundry bodily oozings rather than spray the bed with an extra long burst of febreze.

You wouldn’t season rotten meat in curry then serve it to your in-laws, would you?

Now, to be fair, the purveyors of these products do not intend for you to use their product to allow you to live in filth disguised with the scent of lavender, and their scientists are smart people – however, there marketing departments do need to be brought to book for giving a few misleading impressions.

The world ‘fresh’ for example is used universally. I don’t know about you, but to me this should mean clean, pure and new. It may certainly allow for some sweet floral aroma, but it certainly doesn’t include ‘complex organics we cannot smell’.

Some solutions – like Resolve carpet cleaner, where an absorbent powder is applied liberally then hoovered up, deserve a break – but, as far as I can see there are the exception – most odour control is still in the form of the old “cover up”.

What we have to remember is that in order to claim a product is ‘absorbing’ an odour, one only need prove it absorbs ‘some’ odour – not necessarily the majority and very rarely “all”. Thus it can be that it absorbs 2% of the odour and the other 98% of the odour is still there but overwhelmed by the scent of a pine forest. The same is true with biocidal deodorisers (like Lysol) which may kill bacteria – a common source of odour. These products can actually kill germs – however the impression that a quick spray will effectively sterilise is falsely reassuring.


I sign off now by pointing out that the best way to avoid odours is by good hygiene, though not too good: remember that we humans co-evolved with this slimy little planet!

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.


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!



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!


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.
  • 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: – 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: –


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…