Archive for February, 2012

Ocean Acidity: What is pH anyway?

February 29, 2012

An image of CO2 molecules dissolving in the ocean to create carbonic acid. Image is from the interesting Chemistry Land site. Click image to go there.

The story so far…

Human beings have been emitting carbon dioxide into the atmosphere in ever greater amounts – currently around 30 billion tonnes every year. And about half of that carbon dioxide remains in the atmosphere. But around one quarter – the exact amount is uncertain – is dissolved in the oceans and has caused an increase in acidity, changing ocean  pH from around 8.2 to around 8.1

Oh, you might be thinking – not so serious then: a change from 8.2 to 8.1 isn’t much of a change. Sadly, it is serious: it corresponds to a 25% increase in the number of ‘acid molecules’. So let me explain the pH scale, one of the worst-designed and poorly-named scales in science.

The ‘H’ in pH stands for Hydrogen, and scale seeks to measure the concentration of hydrogen ions in a solution. A hydrogen ion is a hydrogen atom which has had its electron removed. Its symbol is H+ and it consists of a single fundamental particle – a proton. It is uniquely mobile and reactive and the entire chemistry of acids and bases is all about the behaviour of this ion.

I had always wondered what the ‘p’ stood for in pH and Wikipedia tells me that I am not the only one to wonder – its actual meaning has been lost in the mists of time! Originally it may have stood for ‘power’ or ‘potential’.

However rather than just recording the number of ions per unit volume, the scale seeks to make things ‘simpler’. Don’t you just hate that!

  • In nominally pure water, at around room temperature there are around 0.000 000 1 (or 107) hydrogen ions for every water molecule – roughly 1 H+ ion for every 10 million water molecules. The pH scale calls the acidity of pure water 7.
  • In seawater there used to be roughly one hydrogen ion for every 158 million water molecules, or equivalently 0.000 000 0063  (6.3 x 10-9) hydrogen ions for every water molecule. Using fancy maths it turns out that 6.3 x 10-9 = 108.2 and so the pH scale says seawater had a pH of 8.2
  • In seawater now there is roughly one hydrogen ion for every 126 million water molecules i.e. the concentration has increased by around 25% . Equivalently there are now 0.000 000 0079 (or 7.9  x 10-9) hydrogen ions for every water molecule. Using fancy maths one can show that  7.9 x 10-9 = 108.1 a and so the pH scale says this seawater has a pH of 8.1

This 25% increase in ocean acidity is a direct results of the roughly 30% increase in atmospheric CO2. The way in which dissolved carbon dioxide causes water molecules to dissociate more than they otherwise would is complicated – so complicated that it is called Chemistry :-). But trust me: it does.

The acidification is what makes fizzy drinks taste interesting, but what is good news for sparkling water aficionados is bad news for the many kinds of organisms that live in the sea and which form the base of the food chain that sustains the ecosystems of the oceans. Animals that have shells will find it especially hard to cope if CO2 levels continue to increase. This BBC story describes research near underwater volcanos which shows how ecosystems are affected by increased acidity.

Please note: it is all much more complicated than I have made out! Ocean acidity varies from one part of the oceans to another and with depth and … well, there are many factors in play.  But very roughly the pH of mid-ocean sea water has decreased from around 8.2 to around 8.1  and the decrease will continue if atmospheric levels continue to rise.

Science and Technology

February 27, 2012
Science and Technology

How are Science and Technology related? Is one more fundamental than the other? Or they are they inextricably linked?

… or why could Leonardo design a helicopter, but not build one? 

(Steve Lawless)

Science… and Technology. They are often spoken of together in the same breath as if they were siblings, or a married couple. But just how exactly are they related?

First of all let’s look at the etymology of the words. Etymonline tells me that

  • Technology comes from the Greek tekhnologia “systematic treatment of an art, craft, or technique,” .
  • Science comes  from Latin. scientia “knowledge,” from sciens(gen. scientis), prp. of scire “to know,” probably originally “to separate one thing from another, to distinguish,” related to scindere “to cut, divide,”

Very roughly I think this means that ‘technology’  is about how some activity is achieved, and is thus close to engineering in its aims. Science, has the sense of a wider study of not just  ‘how’ but also ‘why’.

So how are they related? I think the diagram at the head of the page captures two interesting features of the inter-relationship.

Firstly, new technology builds on older technology and new science builds on older science. This much we are familiar with. And it is clear that new technology enables new science – think of the atomic force microscope or the computer – technologies that have enabled diverse scientific advances. Similarly science enable new technology, but in general it is not the bleeding edge of science which is built into technology. Technology which is sold has to work! And so, in general, it incorporates the previous generation of science. So the top level of diagram doesn’t have any horizontal lines.

There are exceptions to this structure, and sometimes the generations succeed each other so quickly it all seems like a blur. But what this means is that in general it is not possible to say what science a new technology will enable, or what technology new science will enable. That’s the thing about the future: we don’t know what is going to happen.

P.S. I have to say that this is not my idea – but I can’t find out whose idea it was originally!

Climate Change: Tales from the front line

February 24, 2012
Boiler Gone

The space where our old boiler used to be - now replaced with a new efficient model. I can't wait until my bills start to go down...

You might be forgiven for thinking that Climate Scientisists are on the front line of the war against Climate Change. In fact, the front line is much closer to home – in fact it’s in your home – and mine. And the crack troops are not scientists and engineers, but builders and plumbers. Let me tell you about some collateral damage I witnessed during a recent skirmish.

Just before Christmas I was forced to acknowledge that our central heating boiler wasn’t working. The problem was that while showering, the hot water would cut out for a minute and then return. As Christmas approached it became clear that the period of ‘cutting out’ was getting longer, and that sometimes it just wasn’t working at all. My ‘denial’ strategy wasn’t working.

After debating a repair for roughly £500 with uncertain prospects of success, we replaced the boiler with a new ‘condensing’ boiler for the best part of £2,000. It then immediately showed exactly the same symptoms as the previous boiler! However, the new boiler was so clever that instead of limping along as the old one had done, it immediately diagnosed the problem, displayed an error code, and shut down.

It transpired that the problem had not been with the previous boiler at all, but with the gas pressure. The ‘governor’ on top of the gas meter which regulates the gas pressure in the house was faulty. A (free) emergency callout later and the governor was replaced and everything began to work again. Wonderful: and all in time for Christmas.

Except that … now that the shower became reliable again, the children in particular became less reluctant to us it! And so, despite the new, efficient boiler, our gas use has shot up because the water heating is so reliable.

And I mention this because I just want to make the point that updating fossil-fuel-using plant with new ‘efficient’ plant doesn’t necessarily mean that  consumption, or bills, or emissions, will go down. Nothing is simple!

My big problem with astronomy

February 22, 2012
Pretty Galaxy

A Pretty Galaxy - the subject of erudite speculation by astronomers and mindless reporting by hacks. The circle marks the apparent location of a black hole called HLX-1. Don't believe the colours - the picture is 'data' and not a photograph. The galaxy - which is inferred to be spiral in shape even though we see it edge on - is called ESO 243-49

Recent stories in Wired and The Register illustrate perfectly everything I hate about popular astronomy. First of all, you can see these are both routine hacks by comparing them with the press release.

Don’t get me wrong: I am filled with admiration for astronomers: their instruments are astounding; the maths and physics of observing is inspiring; and of course the Universe is just breathtakingly beautiful. What irritates the pants off me is the ridiculous desire to ‘explain’ what they observe. What we end up with is a pretty picture and a fantastical, unverifiable ‘sciency’ tale. Frankly we would be better of with just the pretty picture and good old fashioned ‘fairy’ tale.

To explain what I mean I have reproduced extracts from the ‘Wired’ article below in blue with what the article should (IMHO) have said.

Wired: The Hubble space telescope has spotted a supermassive black hole floating on the outskirts of a large galaxy.
Actual: Scientists looking at data from the Hubble Space Telescope have inferred the existence of a black hole near a large galaxy.(How?)

Wired: The location is odd because black holes of this size generally form in the centers of galaxies, not at their edges. This suggests the black hole is the lone survivor of a now-disintegrated dwarf galaxy.
Actual: The location is odd because evidence indicates black holes of this size are generally  found near the centers of galaxies, not at their edges. Scientists don’t understand this.

Wired:The black hole — named HLX-1 — is 20,000 times more massive than the sun, and is situated 290 million light-years away at the edge of the spiral galaxy ESO 243-49.
Actual: The black hole — named HLX-1 — is estimated to be 20,000 times more massive than the Sun (how?), and is estimated to be 290 million light-years away at the edge of the spiral galaxy ESO 243-49

Wired: Hubble detected a great deal of energetic blue light coming from the black hole’s accretion disk — a massive collection of gas and dust that spirals into the black hole’s maw, generating x-rays. But scientists studying Hubble’s data also noticed the presence of cooler, red light, which shouldn’t have been there.
Actual: Hubble detected blue light  and red light. They inferred that the blue light came from an accretion disk. But they couldn’t understand the red light.

Wired: Astronomers suspect the red light indicates the existence of a cluster of young stars, roughly 200 million years old, orbiting around the black hole. These stars, in turn, are the key to explaining the chaotic history of the supermassive black hole.
Actual: Astronomers could explain the red light if there were young stars orbiting around the black hole. They even thought up a story about these unobserved stars that might actually exist.

Wired: HLX-1 was likely formed at the center of a dwarf galaxy that once orbited ESO 243-49. But in this dog-eat-dog universe of ours, large galaxies often swallow up their smaller brethren. When the dwarf galaxy came too close to ESO 243-49, the larger galaxy plucked away most of its stars, leaving behind the exposed central black hole. The force of the galaxies’ collision would have also triggered the formation of new stars, explaining the presence of a young stellar cluster around the black hole. The cluster’s age, 200 million years, gives a good estimate of when the merger occurred. HLX-1 may now be following the same fate as its parent galaxy, slowly getting sucked into ESO 243-49. But researchers don’t know the details of the black hole’s orbit, so it could also possibly form a stable orbit around the larger galaxy, circling as the isolated reminder of a vanished dwarf.
Actual: HLX-1 was likely formed when a space dragon called PTMD-X1 laid an egg, which grew into a blue headed X-ray dragon. Astronomers speculate that the dragon’s mother died when it was just 200 million years old  causing the youngster to cry tears which then turned into stars through a process astronomers call tear-star -formification. The blue colour of the stars shows the dragon was sad and astronomers hope that it is happier now and has made friends.

Learning to love accountants

February 20, 2012

Engineering, Procurement and Construction (EPC) costs for different types of power station. The abbreviations are explained in the text and listed at the foot of the blog. The red bars show the basic cost estimate and the blue bars indicate the range of possibilities. To find the cost of a 1 GW power station multiply the costs shown by one million. So the cost to build a 1 GW nuclear power station is roughly 2.5 billion pounds.

What are the relative costs of generating electricity in using the different technologies? This is a simple question to ask, but a difficult one to answer. If we make the wrong decision we end up spending more money than we needed to – and we are all the poorer for it. But how does one compare, for example,  the high capital costs of a nuclear power station with the higher carbon emissions from gas-fired plant?

To get answers to questions like this we need someone in the pay zone above scientists: accountants.

Accounting is difficult and dull and boring. But it is the only way to answer questions like this. While searching the DECC web site to find out how much UK taxpayers subsidise electricity generation from Wind Turbines, I came across this report on electricity generation costs. It is simultaneously fascinating and tedious in the extreme. I will spare you the details and just share with you what I consider the highlights. There are but two!

Highlight#1:Engineering, Procurement and Construction (EPC) costs for different types of power station. The chart at the head of  article shows the range of possibilities. The red bars show the basic cost estimate and the blue bars indicate the range of possibilities. To find the cost of a 1 GW power station – the UK requires around 60 such stations – one multiplies the costs shown by one million: So a 1 GW nuclear power station costs roughly £2,500 x 1,000,000 = £2.5 billion, while the same generating capacity using gas (CCGT) costs only £0.5 billion. Capturing the carbon from a gas station (CCGT +CCS) adds an estimated £0.25 billion to the cost – but no one has actually achieved that yet.

Highlight#2: Lifetime costs.What if carbon fuel prices increase? What about the cost of decommissioning nuclear plant? It is very tricky to compare this scenarios quantitatively but one way is to show all the costs of the plant over its lifetime divided by the number of units of electricity that it will generate (kWh or MWh) over its lifetime.


Costs of different electricity generating technologies expressed per unit of electricity produced over the lifetime of the plant. £100 per MWh is equivalent to 10 pence per kWh - the standard unit of electricity on a domestic bill. (Click for larger version)

This is a fascinating chart showing estimated costs for projects starting in 2013, some of which are the first of a kind (FOAK) and some of which are the nth of a kind (NOAK).  £100 per MWh – the mid-line on the chart – is equivalent to 10 pence per kilowatt-hour. A kilowatt-hour (kWh) is the standard unit of electricity on a domestic bill. I find three facts astonishing on this

  • The costs are similar! Look for example at CCGT with or without CCS and compare it with Onshore wind. The costs are around 10 pence per kilowatt hour – two or three times current costs for gas (CCGT) generation. If this is true, then for heaven’s sake, let’s start making low carbon electricity now!
  • The decommissioning costs of nuclear plant – when averaged over the amount of electricity produced – is tiny!
  • Do the anti-wind campaigners – who are forcing nearly all wind development offshore – really want to pay TWICE as much for the electricity they produce?
So there you have it: two astonishing charts. With data like this, I could learn to love accountants!



Combined Cycle Gas Turbine

Burns the gas in a turbine and then exploits waste heat in a second steam turbine


CCGT with added Carbon Capture and Storage

CCS is an untried and undemonstrated technology

ASC Coal

Advanced Super Critical Coal

Coal plant operating at higher temperatures. Explained here


ASC with added Carbon Capture and Storage

CCS is an untried and undemonstrated technology


Integrated gasification combined cycle

Converts coal to gas and then burns gas and recovers waste heat in a second steam turbine


IGCC with added Carbon Capture and Storage

CCS is an untried and undemonstrated technology

Onshore Wind

Wind turbines on Land

Offshore Wind

Wind turbines in the Sea

EPC costs and running costs are higher than for land based turbines

Offshore Wind R3

Wind turbines in the Sea in Release 3 of available areas

These represent more difficult engineering challenges

3rd Generation PWR

Next generation Nuclear Power: Pressurised Water Reactor

If Newton had had an Apple…

February 17, 2012
Isaac Newton. Just imagine what he might have achieved if he had had an Apple iMac!

Isaac Newton. Just imagine what he might have achieved if he had had an Apple iMac! Image from Wikipedia

Wikipedia kindly tells me that:

It was in the north cloister [of Trinity College , Cambridge] that Isaac Newton stamped his foot to time the echoes and determined the speed of sound for the first time.

By timing the echo (0.36 s) and measuring the distance (63 m) to and from the end wall of the cloisters, Newton was able to estimate the speed of sound. I have been told that he timed the sound by adjusting a clock so that it ‘ticked’ once in just the same time as it took the sound to travel along the cloisters. Then he let the clock run next to a clock that ticked in real seconds to see how how long it took for (say) 100 ticks.

But imagine if he, like me, had an Apple iMac?

He would have measured the distance by using Google Maps:

Google maps

Google maps image of Trinity College using the distance measuring tool determine the length of the cloisters of Nevile Court.

He would have measured the time by simply recording the event and analysing a slowed down version in iMovie.

iMovie Screenshot

iMovie: capable of precision timing measurements

If he had made a precision measurement he would have discovered his theory about sound was wrong. But he didn’t, and he thought his measurements confirmed his ideas. If only he had had an Apple iMac!

Below is a movie of the very cloisters where Newton performed this experiment – and the door at the end is where he lived – and in which rooms he created ideas that changed how we all see the world. Enjoy. Many thanks to Matthew and his friends for a nice day out.

Heat Engines and Water Wheels

February 15, 2012
Trevithick pumping engine (Cornish system).

Trevithick pumping engine (Cornish system). It is an example of 'heat engine', a device that converts heat energy into mechanical work. Figure from Wikipedia:

The culture around science is obsessed with novelty. This is understandable, but in my view regrettable. And nowhere is this clearer than in that most unfashionable of scientific fields: thermodynamics. The name combines thermo – to do with temperature and heat – and dynamics – to do with forces. So very roughly, thermodynamics is the study of what causes heat to move.

Thermodynamics emerged in the early to mid-nineteenth century as scientists around Europe struggled to understand the limits of steam engines. In the latter part of the 18th Century, just getting any amount of mechanical work ‘for free’ was a benefit, but as the miracle of steam became more workaday, engineers struggled to optimise the devices and get the most work output for the least coal input. It must have frustrated engine-owners that they could see hot water and steam leaving their machines – so clearly some energy was not being utilised!

After several years a solution emerged, generally credited to the french engineer Nicolas Léonard Sadi Carnot – even though his work was essentially ignored druing his short life. His conclusion was that despite all the astonishing complexity of heat engines – the maximum possible efficiency was determined by one simple formulae that depended only on the relative temperatures of the hot and cold parts of the engine. And absolutely nothing else.  No clever device, new fuel, or intricate design could overcome this limit.

I want to write lots of things for completeness, but since I have to go bed shortly, I will restrict myself to just one aspect of his description of how heat engines work: they work like a water mills.

The first result of Sadi Carnot’s analysis is that ‘waste’ heat is not ‘wasted’. In fact it is essential to the operation of the device.

  • In a watermill – it is the flow of water which generates mechanical power. Reducing the amount of”waste’ water by preventing water leaving the mill causes the ‘water level’ at the output to rise and eventually no water would flow.
  • In a heat engine – it is the flow of heat which generates mechanical power. Reducing the amount of”waste’ heat by preventing heat leaving the engine cause the ‘heat level’ – or temperature – at the output to rise and eventually no heat would flow

The second result of his analysis concerns the maximum possible efficiency.

  • In a water mill – the maximum amount of mechanical work per litre of water flow that may be extracted is determined just by the difference in ‘water levels’ between the input and the output i.e. the height difference between the input and the output.
  • In a heat engine – the maximum amount of mechanical work per joule of heat flow that may be extracted is determined just by the difference in ‘heat levels’ between the input and the output i.e. the temperature difference between the hot part and the cold part.

This is astonishing. It says that no matter how clever a device one builds: whether it is a steam engine, a gas turbine or a nano-engineered thermoelectric generator, the maximum achievable efficiency doesn’t depend on any details of the device. For sure it it is possible to have one design that is better than another, but nothing can beat Sadi Carnot’s limit

love results like this: simple insights that transcend the particular details of their discovery. And the law that Sadi Carnot discovered? It is called the Second law of Thermodynamics.

Carnot Efficiency

The maximum possible fraction of heat flow through a device that may be turned into useful work – mechanical or electrical. The calculation assumes that heat leaves the device at 20 °C and the calculation depends on the temperature of the hottest part of the device.

Wind Wars

February 13, 2012
The proposed European Offshore Wind Deployment Centre as seen from Balmedie Beach

The proposed European Offshore Wind Deployment Centre as seen from Balmedie Beach. Click for larger version. Picture is from

The proposed European Offshore Wind Deployment Centre as seen from Aberdeen Beach. Click for larger version. Picture is from

The proposed European Offshore Wind Deployment Centre as seen from Aberdeen Beach. Click for larger version. Picture is from

As I write this (5:00 p.m. on Saturday 11th February 2012) wind power is currently  contributing just 0.24 GW of electrical power to the UK grid. This is equivalent to around a quarter of the output from a large modern power station. For the record, the main contributors to our electricity supply over the last 24 hours have been:

  1. Coal – 548.7 GWh – 50.7% of the total – releasing 548,000 tonnes of CO2
  2. Gas – 266.3 GWh – 24.6% of the total – releasing 133,000 tonnes of CO2
  3. Nuclear – 203.4 GWh – 18.8% of the total – releasing (approximately) 0 tonnes of CO2
  4. Wind – 16.8 GWh – 1.6% of the total – releasing (approximately) 0 tonnes of CO2

(1 GWh is the energy contributed when generating 1 GW, for 1 hour).

This is the nature of wind power. Stable weather systems associated with cold winter weather result in very little wind. But as I recorded previously, over the whole of 2011, wind power contributed more than 5% of UK demand – roughly equivalent to not operating 2 large modern power stations. And for several days in December 2011, wind power was generating over 13% of UK demand on that day (roughly 7 GW). In other words 7 large coal power stations could be rested for a few days and their carbon emissions avoided.

But despite this creditable performance, some people still hate wind power. The latest spat involves well-known environmentalist Donald Trump and would be laughable if it weren’t so serious. Mr. Trump has threatened not to despoil the West Coast of Scotland with a golf course and international resort hotel if wind turbines are built 1 mile out to sea! I do hope that Scottish Government will accept Mr. Trump’s offer because 11 Wind Turbines will do more for the environment than anything Mr. Trump has planned.

Wikipedia has a pair of quotes which (for me) sums up Donald Trump:

  • Susan Mulcahy He was a great character, but he was full of crap 90 percent of the time.
  • Donald Trump: I agree with her 100 percent.
I agree with her too, but I think she has underestimated the amount of crap that Mr Trump is full of by around 11%.
On a more serious note, as the pressure on energy prices increases – as I think it will – we need to be clear about the extent to which we are subsidising electricity generated by wind. I have been unable to find out the extent of the subsidy but I suspect is it is several pence per kilowatt hour – not quite as much as the solar energy feed in tariff (£0.41) , but still large. Obfuscation helps no one.


Truly Amazing People

February 10, 2012

Helping a year 8 student test the magnetic properties of Terbium when cooled to -196 degrees Celsius.

I have just spent 4 days talking to children in two of our great local secondary schools: Waldegrave School and Hampton Academy. Over four days I have spoken to nearly 500 children in small groups varying in size from 10 to 30 students.

I think – I hope – that my talks make a small positive difference to most of the students. And I suspect that for one or two students each year, my visit makes a big difference. But it is impossible to tell. However during my visit, one of the teachers overheard a comment from one of the girls to whom I had spoken that morning. She said,

“That man is amazing!”

And their science teacher was kind enough to write it on a card for me. It made me smile: the only feedback I believe is that which arrives randomly and anonymously.  And it is nice to be appreciated. But actually I should have given similar cards to the teachers I met. Being a teacher for a day with boxes of solid carbon dioxide and liquid nitrogen is really quite easy. Being a teacher day after day after day without cryogenic aids is not so easy – and the teachers at these schools were truly amazing, but IMHO, rather under-appreciated.

A Badge made for me by a teacher at Waldegrave School

Global Warming sceptics lose the plot!

February 8, 2012
BEST T Estimate detail

The Air Temperature above the Land Surface of the Earth (1990 -2010) according to the Berkeley Earth Science Group. The data shown are running annual averages of 12 months data (the 'noisy' graph) and running averages of 10 years of data (the smooth graph). What do you think? Is the Land Surface Temperature of the Earth rising?

I hesitate to criticise other scientists: data is often complex and perspectives differ. When it comes to the issue of Global Warming, data is amazingly complex and perspectives differ radically. But I have reached my limit!

A recent opinion piece in the Wall Street Journal by high profile scientists says – summarising – that there is ‘no cause for panic’. The associated WSJ video coverage refers to Global Warming as a ‘hoax’. The comments on the video show utterly irrelevant pictures of snow ploughs!

Friends, colleagues, readers: this is complete nonsense. I don’t want to go on and on about this but the issue is actually breathtakingly simple:

  • Human beings are putting colossal amounts of carbon dioxide into the atmosphere: 30 billion tonnes (-ish) every year. This is roughly 1% of the amount carbon dioxide in the atmosphere.
  • Carbon dioxide absorbs infra-red radiation and is a small part of the greenhouse gas cocktail that warms the Earth by roughly 33 ºC.
  • It would be utterly astonishing if this extra carbon dioxide had no effect – in fact – it is just inconceivable! So the question is: “What effect is it having?”

This is not a right-wing versus left-wing issue: the Financial Times is convinced about the reality of global warming. This a facing-up-to-reality versus not-facing-up-to-reality issue. The scientists are right that ‘panic’ is inappropriate because ‘panic doesn’t help. But everyone should be concerned about this issue. And in my opinion, very concerned.

The Air Temperature above the Land Surface of the Earth according to the Berkeley Earth Science Group. The data shown are running annual averages of 12 months data (the 'noisy' graph) and running averages of 10 years of data (the smooth graph). What do you think? Is the Land Surface Temperature of the Earth rising?

The Air Temperature above the Land Surface of the Earth (1800 -2010) according to the Berkeley Earth Science Group. The data shown are running annual averages of 12 months data (the 'noisy' graph) and running averages of 10 years of data (the smooth graph). What do you think? Is the Land Surface Temperature of the Earth rising?

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