Category Archives: Education

Fun Physics Questions: Does time flow in baby steps?

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Question: is it possible time flows in little steps?

At some small scale, could it be, that time is simply a ‘symptom’ of a sequence of events, or states, that there is no actual time passage ‘between’ those states?

This scenario has interesting implications – it suggests life is a bit like a movie – a series of pictures on a strip of celluloid, or pages in a book, and like a book, while the story may unfold to you at whatever speed you read it, it does not matter how fast you read the story itself still has its own pace.

This doesn’t mean the book has to be pre-written, it can still unfold with utter unpredictability, the book is unfinished if you like – the important point is that we are stuck experiencing the passage of time at a rate determined internally – by the rate of chemical reactions in our brains. The drum beat of those reactions would feel the same no matter how fast or slow they seems to an outside observer. They could even be paused for a few minutes – we could not tell!

Now physicists studying energy balances of sub-atomic particles have seen that energy often seems to come in little chunks (the ‘quanta in’ quantum), and that can imply that time may also be chunky (maybe Planck time?); alas, time chunking has contradictory implications – contradictory to common sense anyway- like infinite energy flux, not to mention infinite speeds, but hey if you can just get your head around some of the workarounds physicists have dreamed up (quantum tunnelling for example) everything’s all right again. I am personally highly suspicious of workarounds, and that is what I think they are!

Anyway, even if you try to get away from quantum weirdness, you get sucked back in – take for example this geometrical example. Consider the relative positions of three point objects (small particles?) moving freely in space: they could, for an instant, line up perfectly, but if your measurement were infinitely accurate, this could only occur for an infinitely small duration so long as the particles are moving. If you try to explain this by saying space is divided up into chunks (like ‘snap to grid’ in MS Powerpoint) you get into geometrical issues that three points cannot always be integer increments apart  (nor even rational increments apart) without breaking the most basic number axioms.

So even if space isn’t chunked, it turns out you can appeal to the uncertainty principle, which handily says you can only measure the position of anything infinitely accurately if you allow its momentum to be anything at all, including infinite – and infinite momentum is exactly what you (temporarily) need if you are bold enough to let time ‘leap’.

So none of these issues with time chunking turn out as solid proofs against the possibility, they just make things more slippery!

Aside: rather than a book, I like to think of our universe as being a bit like a computer program  – I like to think about Pac-man when it plays itself in ‘demo mode’ – in demo mode, used to allure people at the arcade, the computer controls both the ghosts and pac-man. In the computer, a sequence of commands is run in the CPU and the speed of the computer (like the reader of the book) controls the rate at which we ‘see’ the ghost-chase on the screen, but this speed is invisible to pac-man himself – yes the ghosts chase faster across the screen, but he can run faster too.

[youtube=http://www.youtube.com/watch?v=htl_vwkZWHw&NR=1]

Question: Does a time-increment universe allow time travel?

Well I don’t think we can ‘skip’ events out (we have to experience them all), but if we can go somewhere where events are more or less ‘dense’, maybe we can. We will not feel the difference, we will not get any extra life-span, our cells will age just the same – but if a friend had gone to another place is space-time, where events have bigger gaps, he may have aged at a different rate, and when you meet your friend again one of you will have time travelled forward and the other backward relative to one another.

Is this really possible? Well, yes, I think so – this model ties in very well with relativistic time travel: if you assume events are more spaced out (less dense, with bigger ‘leaps’ between them) in areas with more mass nearby. or when moving vary fast, it maps perfectly.

Conclusion

That’s it for now! Of course, maybe time does not leap, I don’t know, but its something I love to think about! Please let me know your thoughts…

Confirmation bias: confirmed as bias.

Atheism, Education, Psychology, Science, Science communication, Skepticism, The scientific method, , , , , , , , ,

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.

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Air Fresheners Exposed!

Education, Science, Skepticism, The scientific method, , , , ,

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.

Nanobot

This cool pic is from hybridmedicalanimation.com

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.

Hurrah!

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.

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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!

Death by KPI. The unintelligent design of the modern company… and what to do about it.

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KPI!

A beginner’s guide to KPIs…

Background, Context and all that…

Some of you luckier readers will be wondering what on earth a KPI is. Alas, many of my readers will know, and rarely will they have a happy tale to tell about them. Let me tell you mine.

You see, to me the story of the KPI is none other than the story of the modern trend to remove the human element (that most fallible of elements) from big business. I propose that there has crept up upon us, starting when we came down from the trees and now coming to its final fruition with the industrial revolution, a situation in which the workings of our society, our organisations, governments, armies or companies, are simply too complicated to be designed or managed by any one person, whatever force his or her personality might possess.

No, the time of the one big man, the head honcho, the brain, scheming away in his tower, is over – and we enter the era, nay the epoch, of the human hive.

For now we see that in order to achieve great things, it is the ability to sort and organise mankind, rather than the ability of each man on his own, that matters most.

I could wander from my thesis awhile to describe a few side effects, for example, to point out the age of ‘middle management’ is here to stay, or to philosophize about the world where no one is actually ‘driving’ and the species is wandering like a planchette on a Ouija board and how this explains why no one seems to be able to steer us away from the global warming cliff just ahead…

But no, I will not be pulled off course, I will return to our good friend, the KPI.

So it seems we have these complex organisms, such as the venerable institution that is the company, that have evolved to survive in the ecosystem that is our global economy. Money is the blood, and people, I fancy, are the cells. And just as no particular brain cell commands us, no particular person commands a company. Just as the body divides labour among cells, so does the company among its staff. We train young stem cells into muscle, tendon and nerve. We set great troops of workers to construct fabulous machines to carry our loads just as our own cells crystallize calcium to make our bones.

Having set the scene thus I must move on, for where are the KPIs in all this?

As clever as the cells of our bodies may be, to choose depending on the whims of circumstance to turn to skin or liver or fat, that is but nothing compared with the cleverness with which the cells are orchestrated to make a cohesive body, with purpose and aim,  with hopes and dreams, and of course sometimes even the means to achieve them. And the question is: how is that orchestration achieved?

Being a devout evolutionist, its is clear to me that it was by no design, but rather by the constant failure of all other permutations that led to the fabulously clever arrangement, and so it is with the organism that is the company.

It is this conviction that leads me to claim, contrary to the preaching of many business schools, that good companies are not designed, but evolve, and by a process of largely unconscious selection. Like bacteria on a petri dish, companies live or die on their choices, and by every succeeding generation, the intelligence of these choices is embroidered into the DNA of the company.

Yes, I am saying that the CEO of Microsoft, or Rio Tinto of Pfizer, is no more sure of his company’s recipe for success than any one cell in your brain is at understanding how it came to be that you can read these words. Ok, maybe that is unfair. They probably have a good shot at reproducing success in other companies, but they only understand how the company works, not why.

It is well to remember that very few of the innovations present in a modern successful company were developed within that company – the system of raising money from banks or through a system of stocks and shares, the idea of limiting liability to make these investments more palatable, of development the of modern contract of employment to furnish staff; nay the very idea that a group of people can actually get together and create the legal entity that is the ‘company’ has been developed over centuries.

Even within the typical office we see many innovations essential to run a business that could never have been ‘designed’ better by single mind – the systems to divide labour into departments – finance, marketing, sales, R&D, logistics, customer service; the reporting hierarchies and methods for making decisions; the new employee checklists, the succession plans, the new product stage-gate system, the call-report database, the annual budget, the balance sheet, the P&L – these are all evolved and refined tools that incorporate generations of brain power.

Whether it is the idea of share options or the idea of carbon copies, the list of machinery is endless and forms the unwritten DNA of the modern company. The company of today has little in common with the farmstead of 300 years ago, and indeed, just like the bullet train, it would not work too well if taken back in time 300 years. It only works in its present setting. It is part of a system – an ecosystem.

Now a business tool that has been evolving for some time, slowly morphing to its full and terrible perfection is the Key Performance Indicator or KPI.

The Key Performance Indicator

There is a saying in engineering circles: you cannot improve what you do not measure.

This philosophy accidentally leaked to the business community, probably at Harvard, which seems a great place to monetize wisdom, and so there is presently a fever of ‘measurement’ keeping middle managers in their jobs, and consultants on their yachts.

This sounds reasonable – but let’s pick at it a little.

When the engineer installs a sensor in a reactor to measure its pressure, it is usually just one element in a holistic system of feedback loops that use the measurement in real-time to control inputs to that reactor. Thus we can see that measurements in themselves are not enough, there needs to be an action that is taken that affects the measured property – a feedback loop.

Likewise any action taken in a complex system will tend to have multiple effects and while you may lower the pressure in a reactor, you may raise it somewhere else, thus the consequences of the action need to be understood.

And lastly, if the pressure in the reactor is now right, the value of the knowledge has diminished, and further action will be of no further benefit.

So just like a body, or a machine, a company needs to be measured in order to be controlled and improved, and it occurs to me that these key measurements, the KPIs, need to fulfil a similar set of requirements if they are to be of value.

A few years ago I decided to write a list of KPI must-haves, which I present here:

  1. the property measured must be (or correlate with) a company aim (eg profitability)
  2. measurements need to taken to where they can be interpreted and acted upon, using actions with predictable effects, creating a closed loop
  3. the secondary effects of that action need to be considered
  4. repeat only if the benefits repeat too

Now let’s take a look at some popular KPIs and see if they conform to these requirements.

Production KPIs

There are a multitude of KPIs used the ‘shop floor’ of any enterprise, be it a toothpick factory, a bus company, a florist or a newspaper press. Some will relate to machines – up-time metrics, % on time, energy usage, product yield, shelf life, stock turns – indeed far too many to cover here, so I will pick one of my favourites.

“Availability” is a percentage measure of the fraction of time your machine (or factory or employee) is able to ‘produce’ or function. If you have a goose that lays golden eggs, then it is clear that ‘egg laying activity’ will correlate with profits, so point #1 above is satisfied, and measuring the egg laying frequency is potentially worth doing. If you then discover that your goose does not lay eggs during football matches you may consider methods to treat this, such as cancelling the cable subscription. A few trials can be performed to determine if the interference is effective, proving #2. Now all you need to do is worry about point #3; will the goose fly away in disgust at the new policy?

What about #4? Indeed you may get no further benefit if you continue to painstakingly record every laying event ad infinitum. KPIs cost time and money – they need to keep paying their way and may often be best as one-off measures; however, what if your goose starts to use the x-box?

So that is an example of when the KPI ‘availability’ may be worth monitoring, as observing trends may highlight causes for problems and allow future intervention. So surely availability of equipment is a must-have for every business!?

No. There are many times when plant availability is a pointless measure. Consider for example an oversized machine that can produce a year’s supply in 8 minutes flat. So long as it is available for 8 minutes each year, it does not matter much if it is available 360 days or 365 days. Likewise, if you cannot supply the machine with raw materials, or cannot sell all the product it makes, it will have forced idle time and availability is suddenly unimportant.

The simplest way to narrow down which machines will benefit from an availability or capacity KPI is to ask: is the machine is a bottleneck?.

For other types of issues, let’s look at some other KPIs.

Quality KPIs

Quality KPIs are interesting. Clearly, it is preferable to ship good products and have happy customers. Or is it?

In any production process, or indeed in any service industry, mistakes will be made. Food will spoil, packaging will tear, bits will be left out. It is now fashionable to practice a slew of systems designed to minimise these effects: to detect errors when they are made, to re-check products before they are shipped, to collect and collate customer complaints and to feed all this info back into an ever tightening feedback loop called ‘continuous improvement‘.

KPIs are core to this process and indeed KPIs were being used in these systems long before the acronym KPI became de rigueur. To the quality community, a KPI is simply a statistic which requires optimization. The word ‘Key’ in KPI not only suggests it represents a ‘distillation’ of other numerous and complex statistics, but implies that the optimising of this particular number would ‘unlock’ the door to a complex improvement.

Thus, a complex system is reduced to a few numbers, and if we can improve those numbers, then all will be well. This allows one to sleep at night without suffering  nightmares inspired by the complexity of one’s job.

The reject rate is a common quality KPI – it may encompass many reasons for rejection, but is a simple number or percentage. It is clearly good to minimize rejects (requirement #1) and observing when reject rates rise may help direct investigations into the cause thereof satisfying requirement #2.

However, from rule #2 we see that this KPI is only worth measuring if there will be follow-up: analysis and corrective action. This must not be taken for granted. I have visited many plants that monitor reject and when asked why, they report that head office wants to know. What a shame. Perhaps head office will react by closing that factory some time soon.

The failure to use KPIs for what they are intended is perhaps their most common failure.

Another quality KPI is the complaint rate. Again, we make the assumption that complaints are bad, and so if we wish to reduce these we should monitor them.

Hold the boat. How does the complaint rate fit in with company aims? We already know that mistakes happen, but eliminating quality issues is a game of diminishing returns, so rather than doggedly aiming for ‘zero defect’ we need to determine what complaint rate really is acceptable.

So here is another common KPI trap. Some KPIs are impossible to perfect, and it is a mistake to set the target at perfection. Think of your local train service. Is it really possible for a train system to run on time, all the time? The answer is an emphatic no!

The number of uncontrolled inputs into a public transit system – the weather, the passengers, strike actions, power outages and the like will all cause delays, and while train systems can allow more buffer time between scheduled stops to cater to such issues, this type of action actually dilutes other aspects of service quality (journey frequency and duration). Add to that finally the fact that a train cannot run early so losses cannot be recovered.

The transport company will of course work to prevent delays before they occur, and lay on contingency plans (spare trains) to reduce impacts, but the costs and practicality mean that any real and meaningful approach needs to accept a certain amount of delays will be inevitable. A train company could spend their entire annual profit into punctuality and they would still fall short of perfection.

So it is with most quality issues, the law of diminishing returns is the law of the land. Thus the real challenge is to determine at what point quality and service issues actually start to have an impact on sales and cashflow. This is another common pitfall of the KPI…

The correlation between the KPI and profitability is rarely a simple positive one, especially at the limits.

Some companies get no complaints. Is this good? No, often it is not! This company may be spending too much money on QC. The solution here is to work with and understand the customer – what issues would they tolerate and how often? If you did lose some customers by cutting quality, would the financial impact be greater than the savings?

However, and on the other hand, don’t make the opposite mistake: once a reputation for poor quality is earned, it is nearly impossible to shake.

Financial KPIs

As companies become bigger, there is a tendency to divide tasks according to specialized skill and training. Thus it can happen that the management of a big mining company may never set foot in a mine, may not know what their minerals look like, nor may they know how to actually dig them up or how to make them into anything useful. In other words, they would be useless team members after a nuclear apocalypse.

However, this is no different from our brain which is little use at growing hair, digesting fat or kicking footballs.

It is thus necessary that the organism (the company) develops a system to map in a flow of information from its body to its mind and then another mapping to take the decisions made in that mind and distribute them to the required points of action.

Indeed to blast in a quarry, or to kick the football are indeed best done by organs trained and capable and no less important than the remote commanders in the sequence of events.

And just as our bodies have nerves to transmit information about the position of our lips and the temperature of the tea to our mind, so the company has memos, telephones and meetings. And KPIs are the nouns and subjects in the language used.

Furthermore, some KPIs need to be further distilled and translated from the language of the engineer (Cpk), the quality manager (reject rate) or the plant manager (units shipped) to that of the accountant (revenue) , the controller (gross margin) and eventually that of the general manager and the shareholder (ROI). This is perhaps the main duty of middle management, bless their cotton socks.

Unfortunately, the mapping of everyday activities to financial KPIs is fraught with danger. The biggest concern comes from the multiple translation issue. That is to say, KPIs can suffer from a case of Chinese whispers, losing their true meaning along the way, resulting in the worse result: a perverse incentive.

Yes, ladies and gentlemen, this does happen.

Let’s say you want to improve your cash situation. You may choose to change the terms in your sales contracts for faster payment, in essence reducing the credit you allow your customers. This may have the desired effect, lowering the KPI  called “receivables” and this looks good on the balance sheet – but let’s look at requirement #3 in the KPI “must have” list. What are the ripple effects of this move? It is clear this will not suit some of your customers, who, considering recent economic trends, probably also want to improve their cash situation; thus you may lose customers to a competitor willing to offer better terms.

And so we see the clear reason for perverse incentives is the consideration of KPIs individually instead of collectively. There has to be a hierarchy upon which to play KPIs against one another. Is revenue more important than margin? Is on-time shipping a part-load preferable to shipping “in full” a little late?

So we see again that the systems used to distill company indicators the choice of which decisions are centralized and which are localized need to be developed and constantly refined using an iterative process. The art of translating the will of shareholders into a charter or mission statement and then translating that into targets for sales, service and sustainability is a task far too complex to perfect at first attempt.

KPI Epic Fails

While on the subject of KPIs I cannot resist the opportunity to bring to mind a few fun examples of KPIs gone badly wrong.

The Great Hanoi Rat Massacre

The French administration in Hanoi (Vietnam) were very troubled by the rat population in Hanoi around the start of the last century, and knowing as they did about rat’s implication in the transmission of the plague, set about to control the population. A simple KPI was set – “number killed” and payments were made to the killers on this basis. There was immediate success with rats being brought in by the thousand and then the tens of thousand per day. The administration was pleased though somewhat surprised by the sheer number. There surprise gradually transformed into disbelief as time wore on and the numbers failed to recede.

You guessed it. The innovative residents of Hanoi had started to breed rats.

The Magic Disappearing Waiting List

Here’s a more recent example from the National Health Service in the UK (the NHS).

A health service is not there to make a profit, it is there to help the population, to repair limbs, to ease suffering, to improve the length and quality of life – and to do this as best it can on a finite budget. So the decisions on where to invest are made with painstaking care – and needless to say, KPIs are involved. Not only big picture KPIs like life-expectancy, or cancer 5-year survival rates, but also on service aspects, such as operation or consultation waiting times.

It will therefore not be surprising to you to learn that the NHS middle management started to measure waiting times and develop incentives to bring these down, or even eliminate them. This sounds very reasonable, does it not?

Now ask yourself, how do you measure a waiting time? Say a surgery offers 30 minute slots – you may drop in and wait for a vacant slot, but as the wait may exceed a few hours it is just as well to book a slot some time in the future and come back then. So one way to measure waiting times is to measure the mean time between the call and the appointment. This of course neglects to capture the fact that some patients do no actually mind the wait and indeed may choose an appointment in two weeks time for their own convenience rather than due to a lack of available slots. Lets put that fatal weakness aside for the minute as I have not yet got to the amusing part.

After measurements had been made for some time, and much media attention had been paid to waiting times, the thumb-screws were turned and surgeries were being incentivized to cut down the times, with the assumption they would work longer hours, or perhaps create clever ‘drop-in’ hours each morning or similar.

Pretty soon however, the results started coming in, the waiting times as some surgeries were plummeting! Terrific news! How were they doing it?

Simple: they simply refused to take future appointments. They had told their patients: call each morning, and the first callers will get the slots for that day. This new system meant nobody officially waited more than a day. Brilliant! Of course it is doubtful the patients all felt that way.

How The Crime Went Up When It Went Down

If you work for the police, you will be painfully aware that measuring crime is difficult. And so it is with the measurement of many ‘bad’ things – for example medical misdiagnoses or industrial safety incidents.

Let’s look at workplace safety; while it may be fairly easy to count how many of your staff have been seriously injured at work, it is much harder to record faithfully the less serious safety incidents – or more specifically, the ones that might have been serious, but for reasons of sheer luck, were not. The so-called ‘near-misses’.

Now to the problem. Let us say you are a fork-lift driver in a warehouse and one day, it a moment of inattention, you knock over a tower of heavy crates. Luckily, no-one was around and more luckily, no damage was done. So what do you do? Do you immediately go to the bad-tempered foreman with whom you do not get along and tell him you nearly killed someone and worse, nearly caused him a lot of extra work? Or do you carefully stack the crates again and go home for dinner?

The police suffer a similar predicament. The reporting of a crime is often the last thing someone wants to do, especially if they are the criminal. Now let’s say you are an enterprising young administrator just starting out in the honourable role as a crime analyst at the Met. You want to tackle crime statistics in order to ensure the most efficient allocation of funds to the challenges most deserving thereof. Do bobbies on the beat pay for themselves with proportionately reduced crime? Does the ‘no broken windows‘ policy really work? Does the fear of capital punishment really burn hot in the mind of someone bent on murderous revenge? Such are the important questions you would wish to answer and you have a budget to tackle it. What do you do?

You set out to gather statistics of course, and then to develop those tricky little things, the KPIs.

Now let’s say a few years pass, and after some success, you are promoted a few times and your budget is increased. Yay! You have always wished for more money to get more accurate data! Another few months later and the news editors are aghast with the force. Crime is up! Blame the police – no, blame to left – no blame the right! Blame the media! It’s video games – no, it’s the school system!

No, actually it’s a change in the baseline.  The number of crimes recorded most likely went up because the effort in recording them went up. The crime rate itself may well have gone down.

The opposite can also happen. Say you run a coal mine and you will be given a huge bonus if you can get through the year with a certain level of near misses. Will you really pressure your team to report every little thing? I think not.

So the lesson here is: watch out for a KPI where you want the number to go one way to achieve your longer term aims, but where the number will also depend on measurement effort.

The Profit Myth

Most KPIs are dead dull. The very mention of KPIs will elicit groans and be followed swiftly by a short nap. The ‘volume of sales’ KPI is no different. The issue with the volume KPI is probably made worse by the clear fact that actually thinking about KPIs is a strong sedative. Surely selling more is good? Well, if you can fight through the fog of apathy, and actually think about this for a second, it is easy to see this is often not so.

To see why, it is important to understand price elasticity. It if often true that lowering price will increase sales, so an easy way to achieve a target ‘volume’ (number) of sales is to drop price. That way to can make your volume KPI look good, as well as your revenue KPI, and so long as there is still a positive margin on all the units sold your earnings KPI (aka profit!) will see upside. There can’t possibly be any downside, can there?

Of course, astute financial types can find this fault easily, and perhaps the question of ‘how’ would make a good one for a job interview. It turns out more profit is not always good (seriously!). Whether more profit is really worth taking depends on the ratio of the increased earnings to the increased investment that is needed to make them.

There is another KPI I mentioned earlier the “ROI” or return on investment. When I discussed it I implied that it was only of interest at the GM level, but really the reason only the GM tends to see this KPI is because it is difficult to calculate, and often only the GM has the clout to get it – but it should be considered by all. To me, it is the king of KPIs for a publicly listed company. And it turns out the ROI may actually go down with increasing profit.

If making more widgets requires no further investment, then the maths is easy, but that is rarely true.

The question is this: is it better to have a large ‘average’ business or a smaller one with higher profit margins? It turns out, from an investor’s perspective, that the latter is fundamentally preferable.

The ROI treats a business a bit like a bank account: asking what interest rate does it offer? The business should be run to give the highest interest rate‘(%), not the highest interest ($). It is always possible to get more interest from a bank account – just put more money in the bank.

Translating a Mission Statement into company KPIs

I mentioned above that the ROI is a pretty darn good KPI – so can we use it alone? Of course not. Recall that the KPIs are mere numbers we measure that try to tell us how we are doing against the company mission statement, and while the company mission statement may unashamedly describe vast profits as a goal, this is almost universally not the whole story.

The organism that is the modern company has one particular need besides profit today, and that is profit tomorrow. The ROI does not capture this need, so more KPIs are required, and trickier ones – ones that capture sustainability, morale, innovation and reputation (brand value). This is the turf of the mission statement.

Even though the more cynical of my readers will know the mission is usually ‘make lots of dosh’, and anything beyond that is window dressing, I would venture that the mission statement is the first step to figuring out which KPIs to put first.

Let’s dissect a few examples. In my own 2-minute analysis I decided they fall into four types:

  1. To appeal to employees:
    McGraw Hill:
    We are dedicated to creating a workplace that respects and values people from diverse backgrounds and enables all employees to do their best work. It is an inclusive environment where the unique combination of talents, experiences, and perspectives of each employee makes our business success possible. Respecting the individual means ensuring that the workplace is free of discrimination and harassment. Our commitment to equal employment and diversity is a global one as we serve customers and employ people around the world. We see it as a business imperative that is essential to thriving in a competitive global marketplace.
  2. To appeal to customers (aka the unabashed PR stunt)
    A recent one from BP:
    In all our activities we seek to display some unchanging, fundamental qualities – integrity, honest dealing, treating everyone with respect and dignity, striving for mutual advantage and contributing to human progress.
    I couldn’t leave this one out from Mattel:
    Mattel makes a difference in the global community by effectively serving children in need . Partnering with charitable organizations dedicated to directly serving children, Mattel creates joy through the Mattel Children’s Foundation, product donations, grant making and the work of employee volunteers. We also enrich the lives of Mattel employees by identifying diverse volunteer opportunities and supporting their personal contributions through the matching gifts program.
  3. To appeal to investors. This is usually a description of how they are different or what they will do differently in order to achieve big dosh.
    CVS:
    We will be the easiest pharmacy retailer for customers to use.
    Walt Disney:
    The mission of The Walt Disney Company is to be one of the world’s leading producers and providers of entertainment and information. Using our portfolio of brands to differentiate our content, services and consumer products, we seek to develop the most creative, innovative and profitable entertainment experiences and related products in the world.
  4. For the sake of it – some companies clearly just made one up because they thought they had to, and obviously bought a book on writing mission statements:
    American Standard’s mission is to “Be the best in the eyes of our customers, employees and shareholders.”

Now a great trick when analysing the statement of any politician, and thus any mission statement, is to see if a statement of the opposite is absurd. In other words, if a politician says “I want better schools”, the opposite would be that he or she wants worse schools, which is clearly absurd. Thus the original statement has no real content, it is merely a statement of what everyone would want, including the politician’s competitors. Thus to judge a politician, or a mission statement, it is important to look not at what they say, but at what they say differently from the rest.

Mission statements seem rather prone to falling into the trap of stating the blindingly obvious, and as a result become trivial, defeating the point. Such is the case with American Standard. Of course you want to be the best. And of course it is your customers, employees and shareholders who you want to convince. Well no kidding!

So discounting those, we can see that a good mission statement will focus on difference. If we look at CVS, their mission is to be easy to use. This may seem like a statement of the obvious, but I don’t think it is – because they have identified a strategy they think will get them market share. Now they can design KPIs to measure ease of use. This is the sort of thinking that led to innovations like the ‘drive-thru’ pharmacy.

If we look at Disney, you can go further. “…[To] be one of the world’s leading producers and providers of entertainment…” OK, so they admit being #1 is unrealistic, and if you want to be taken seriously, you need to be realistic. But if you are one of many, how do you shine? “Using our portfolio of brands to differentiate” They realise they can sell a bit of plastic shaped like a mouse for a lot more than anyone else can. There is a hidden nod to the importance of brand protection. So KPIs for market share and brand awareness fall right out. They finish off with “the most creative, innovative and profitable entertainment” Well you can’t blame them for that.

Very rarely, you see a mission statement that not only shows how the company intends to make money, but may also inspire and make pretty decent PR. I like this one from ADM:

To unlock the potential of nature to improve the quality of life.

I have no idea how to get a KPI from that though!

Summary

In this article I have tried to illustrate how measuring a KPI is much like taking the pulse of a body – it’s a one-off health check, yes, but more importantly it can be a longer term measurement of how your interventions are affecting company fitness in the longer term.

I also try to describe some common pitfalls in the use of KPIs and presented four simple tests of their value:

  1. the KPI must correlate to a company’s mission
  2. the KPI must form part of a corrective feedback loop
  3. perverse incentives can be avoided by never considering any single KPI in isolation
  4. repeat the treatment only if the benefits repeat too

I have personally used this checklist (with a few refinements) over the years to some good effect in my own industry (minerals & materials) and though I am confident many of my readers will have more refined methods, I live in hope that at least one idea here will of benefit to you.

Reality: a hard sell

Atheism, Education, Science, Skepticism, , , , , , , , , , , , ,

I can’t help but wonder if doggedly debunking all spewings from the purveyors of woo is somewhat a fool’s errand.

There are a number of pseudo-scientific disciplines whose concepts are inherently highly attractive and contagious to the average Joe, saying things that make him feel good and making him want to pass on the good news. Think of how easy to sell these messages are:

  • organic food – frolicking chickens, steaming compost, happy farmers, healthy food – a return to basics, back to a purer time when humans actually had roots in the earth and cared for it; you too can go organic!
  • complimentary medicine – age-old wisdom, so long suppressed by big pharma is unlocked just for those open-minded enough to look. Are you open-minded! Yes? Here are your keys to healthy prosperity!
  • astrology – our fates, entwined with the universe, form a beautiful unity; enigmatic scholars have acted custodian to its cipher through the ages. Are you a spiritual soul? You too can share time’s secrets!
  • parapsychology – our minds are more powerful than science knows, and we all have potential beyond our wildest dreams! But hold on! Only those willing to break free from the trappings of conventional science will ever see the light…
  • and of course the big kahuna, religion – imagine for a minute the greatest most wonderful thing in all the world, and that is but nothing compared with the joys that await the believer, and for all eternity too!

It is little wonder the bible I had as a kid said “Good News” on the cover.

The issue is that the logical shredding of these pieces is often a sobering dose of reality that fills most people with instant sleepiness:

  • organic food is not always kinder to the planet and claimed health benefits are of the ‘hard to verify’ sort
  • alternative medicine actually does work, but only the level one would expect from getting time, care, attention and the placebo effect
  • the laws of physics do allow marvellous things (x-rays, computers, holograms) but it takes serious study to understand why they don’t allow for the positions of stars and planets to have predictable effects of the day-to-day ongoings in suburbia.
  • the mind is indeed fabulously clever and poorly understood, but those tedious laws of physics, and indeed dry, cold logic, are annoyingly sticky when it comes to clairvoyance, ESP, psychokinesis and precognition.

So YAWN! Boring!! Logic and analysis mean effort, work, thinking things through, totting up totals, cross-checking claims, testing, questioning and doubting. Pretty much the opposite of nice & easy. Accepting we are not all-powerful, we are not immortal and that we will all be forgotten someday is just no fun. These are not messages that will go viral, that will breed missionaries, that would generate a manic fervour. More like manic depression.

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So the deck is stacked. Pseudo-scientific ideas persist because they are tenacious memes, and they are almost impossible to kill. They are contagious and sticky, and lovely and easy, and fighting them off requires not just the will, but also the ammunition.

And that is why it worthwhile to continue to fight the good fight – to keep trying to debunk poor thinking – to provide the ammunition to that small number, those that may be on their own, surrounded by superstition, but with that gift in their heart that is that first inkling of doubt.

I will do it for those that think they are alone as I once did.

We live in a time of unprecedented opportunity – people have better access than ever to the tools to arm themselves to achieve a new sort of ideal: to make life choices with full access to all the facts. We are after all free to choose to believe anything, the problem only comes when we are not given the choice. No information, no balance, no choice.

Hysteresis Explained

Education, Environment, Science, Science communication, The scientific method, Things Explained, Time, , , , , , , , , ,

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!

 

 

Learning

Education, Psychology, Science, Skepticism, , ,

It seems to me there are three elements to a good education:
1. A stimulating environment. In such an environment, everyone will learn furiously.
2. Selection. That is to say, the ratio of useful/constructive things learned, vs useless/wrong/just plain destructive things we learn in the abovementioned stimulating environment.
3. No sugar coating. Nobody who learns only wholesome, proven, positive things will be well educated. An essential aspect of a good education is learning by error and embarrassment, loss, sorrow, breakage, cheating, lying and heartbreak.

So because an education requires fault and deception, there cannot be a perfect education, only a more or less effective one for one’s environment…

Stuff I Wish I Had Read When I Was Younger

Economics, Education, Evolution, Mathematics, Philosophy, Psychology, Science, Science communication, Skepticism, The scientific method, , , , , , , , , , , , , , , , , , , , , , , , , , ,

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?

Education, Environment, Physics, Science, Science communication, The scientific method, Things Explained, , , , , , , , ,

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.

[youtube=http://www.youtube.com/watch?v=Pmy5fivI_4U]

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.