Archive for May, 2011


May 31, 2011
A woman engaged in a WHO category 2B activity

A woman engaged in a WHO category 2B activity

Today I read that the World Health Organisation have classified use of a mobile phone in the same category as drinking coffee, eating pickled gherkins, or wandering through fern bracken: ‘possibly’ carcinogenic. While I don’t disagree technically with this categorisation, I think their decision is asinine and unhelpful.

As we cover in detail in the Protons for Breakfast course, there is a potential hazard associated with use of a mobile phones. Exposure to high intensity microwave radiation is definitely hazardous – ask any microwave meal – but exposure from use of a mobile phone is calculated to be low enough that the risk of damage is small or zero. The WHO categorisation essentially says that it cannot be ascertained whether the risk is zero (category 3) or small (category 1). Since there is no strong evidence of harm (‘probably ‘ carcinogenic = category 2A) they called it category 2B – ‘possibly carcinogenic’. And there I predict, it will stay for ever. The perfect safety of something, like the absence of blue swans, can never be established.

Despite the absence of an increase likely candidate cancers – it is possible that use of  mobile phones could conceivably cause cancer. The problem with the categorisation is that for most people it doesn’t help them to make significant decisions in their lives. It would, for example, be more helpful for all concerned if the naming of category 2B was changed from

  • 2B = ‘possibly does cause cancer, but we don’t know for sure yet’


  • 2B = ‘probably doesn’t cause cancer, but we don’t know for sure yet’.

And then, coffee in hand, we could walk with our pickled gherkins through the bracken and call our friends and tell them that they didn’t need to worry so much.

The Nuclear Issue in Germany

May 30, 2011
A German Anti-Nuclear Protester

A German Anti-Nuclear Protester

I was astounded to hear this morning that the coalition government in Germany has decided to abandon generation of electricity using nuclear power, choosing to close all nuclear power plants by 2022. My first reaction was ‘They have gone bonkers!’ but through the day I have let news percolate in my mind and as I write this at 10:15 p.m. I am really not all sure – but I will be very interested to find out.  I will write more about this in future – I would particularly like to compare the breakdown of generation in the UK and Germany – but for now let me just compare and contrast the conventional economic view; the German approach; the UK approach. And finally, I will say what I would do if I ruled the UK :-).

This decision has not been driven by economics. The ‘economic’ way to generate electricity is to burn coal and gas, of which there is plenty available – perhaps more than we thought. The energy density is high and the technology is well understood. The downsides to burning fossil fuels and getting the cheapest electricity possible are that:

  • The fuels emit carbon dioxide – and we are burning them in ever increasing quantities. In all likelihood, this will create problems in coming decades on a scale too large to fully appreciate.
  • The fuels are not sustainable – and eventually we will need to find alternatives.

However, all the alternatives are more expensive. The ‘economic’ solution is to wait until the price of fossil fuels rises to the point that sustainable energy generation is cheaper, and then the market will drive the growth of sustainable electricity generation. An alternative would be to estimate the (frankly) un-estimatable damage caused by carbon dioxide emissions and add this to the costs of fossil fuel generation through a carbon tax. But the uncertainties are so great that the correct ‘economic’ level of the tax is really nothing more than a guess.

The German approach is driven by politics: the Greens won’t support the government unless it stops nuclear electricity generation. The Green view appears to be that nuclear power – in and of itself – is bad, and that rising carbon dioxide emissions are a price worth paying. This view appears to have widespread support in Germany, and although I sympathise, I basically disagree. The most bizarre element of the agreement appears to be a plan  to  engineer a 10% cut in electricity use. How? Well this might be achieved by a massiveprice increase or by ‘rationing’. ‘Rationing’ might involve legislation to ban shop lighting after a certain hour, or street lighting, or specifying that electricity usage above a certain level is anti-social and to be charged for punitively. From a UK perspective, any of these options looks extremely unrealistic, which just adds up to higher carbon dioxide emissions.

The UK approach is also driven by politics: basically no politician wants to take any responsibility for actually making a decision. The strategy is to ‘let the market decide’. If this is genuinely the policy – and I find it hard to tell if this is just a front – then no matter what the Government say, new nuclear power stations will not be built be in the UK because following Fukushima they will be uninsurable. If in fact the plan is to subtly subsidise nuclear power – which I suspect is the case – perhaps by setting a limit to liability, then we may have nuclear power. But we have no plans to reduce electricity usage – in fact quite the opposite. We subsidise renewable energy generation, but the amount of renewable energy generated is still – frankly – negligible, and plans for its growth still seem tentative.

My view is… that ‘the electricity market’ is not a genuine market and that it is unlikely provide appropriate solutions for the UK. In particular,  the market has no obligation to act in the best interests of the UK – particularly not over the timescale of decades that building electricity infrastructure requires. If investing ÂŁ1billion in Indonesia will make a company more money than in the UK, then they will not bother to invest in the UK. It’s not that the company is evil, it’s that that’s just business. So the UK ends up competing to offer the best return on investment to companies – instead of companies competing to offer the best value to the UK. Personally I think that the electricity infrastructure, like the road infrastructure or the rail infrastructure, is best planned by a single entity with public representation. Come back CEGB – all is forgiven.

The Rudiments of Wisdom

May 30, 2011
Rudiments of Wisdom Book Cover

The Cover of Tim Hunkin's Book, the Rudiments of Wisdom

What is Wisdom? Well I don’t know, but I suspect that it begins with learning, and for many many years I have been an admirer of Tim Hunkin’s ability to take a complex topic and present it straightforwardly to anyone who could read a few paragraphs and enjoy a silly cartoon. Tim Hunkin doesn’t offer wisdom, but he does suggest that the rudiments of any subject, however apparently abstract, can me made accessible. In a way he was the forerunner of many ‘<Complex Topic> made simple’ guides with his simple text and delightful pictures

I was reminded of him the other day when I came across some videos he made for Channel 4 in the 1980’s on the Secret Lives of Machines. The videos delighted me because they took their time – they spent 30 minutes explaining how a vacuum cleaner >actually< works – something unthinkable for a modern day video editor. Nowadays these programs would be just 7 minute slots in a magazine programme.

Anyway, for the record:


Science takes my breath away

May 24, 2011
The NPL-Cranfield Resonator

The NPL-Cranfield Resonator: Click for large version

Today at 5:00 p.m. I was keen to get home and begin cooking dinner but I just wanted to wait for my colleague Robin to finish processing a set of data that we had begun at 7:30 a.m. this morning. I watched as the long awaited data point appeared on the screen – exactly at the position we had anticipated.

  • Our prediction was based on mathematical analysis of the sound field inside a slightly non-spherical cavity, and the effect we were measuring was caused by the fact that at lower pressure molecules travel for longer distances before colliding with other molecules. At half an atmosphere they travel almost 0.001 mm before colliding.
  • Our measurements are measurements of the frequency of sound resonances inside a beautifully-crafted, not-quite spherical cavity. The experiment involves flowing ultra-pure and ultra-dry argon gas through the cavity while measuring with microwaves and microphones and pressure meters and flow meters and thermometers. We had to measure more than a hundred resonances in order to be able to average them well enough to see this tiny shift in frequency – it amounts to only around 5 parts in a million of the speed of sound. If we were measuring a length, the shift would be around 5 millimetres in a kilometre – and we could tell that it was 5 millimetres and not 4.9 millimetres.
And our measurements agreed with our predictions! Somehow, we have made this enormously complex machine behave in a way that isn’t just random, but reflects  the fundamental properties of the argon gas inside it. Sometimes, the fact that it all makes sense, just takes my breath away.

World Metrology Day

May 23, 2011
World Metrology Day

World Metrology Day was the 20th May, celebrating the anniversary of the signing of the convention of the metre in 1875.

Last Friday was World Metrology Day and – it being our line of work – NPL made a bit of a fuss, asking staff to take photographs of a day at NPL. There are some lovely photographs here, but it was a photo sent to me this morning by a colleague that summed it all up for me:

Can you trust this duck to tell you the temperature?

He wanted to know how well he could trust this duck for determining the temperature of his young daughter’s bath water? And it is this question – How do I know if I can trust a measurement? – that is actually the nub of everything we do at NPL.

So I took a few minutes to advise my colleague about temperature measuring technology, outlining the likely uncertainty of measurement for different thermometers. And the outcome of this is that he may well bring in his duck for calibration. Or alternatively he could of course just use his elbow like his parents did:-)

Bob Dylan Quiz

May 23, 2011
Young Bobby Dylan

Young Bobby Dylan: Seventy years old on May 24th 2011

Just in case you are not already sick of people ‘hailing’ Dylan’s genius on the occasion of his seventieth birthday, here is a short quiz for people who are familiar with his oeuvre. If you don’t like Dylan, you should move on to the next post which will be about World Measurement Day.


  1. As whom was Einstein disguised? And for what was he famous?
  2. Where does infinity go on trial?
  3. Why is there no use workin’ or jokin’?
  4. What don’t you need to know which way the wind blows?
  5. Who should be notified that a burning wheel might explode?
  6. Why should the customer be told that nothing was delivered?



  • Less than one: Never mind, but too much of nothing could make you feel ill at ease.
  • One or more: Well done!


May 23, 2011
Q's Ice Cream Corner

Q's Ice Cream Corner at Teddington School's James Bond event.

Most of the weekend has been taken up preparing for, and then clearing up from, serving instant Ice Cream at Teddington School’s James Bond PTA event. One way or another the whole family lent their support: Maxwell helping move the equipment; Stephanie serving ice creams; and Christian playing in the Jazz Band. In between moving boxes hither and thither, I was carrying out experiments – some of the tail-end experiments for the Boltzmann project. And overall the whole weekend has left me feeling simulataneously knackered, but still unable to sleep – a combination of feelings ideally suited to blogging 🙂

Anyway, I tweaked a few recipes compared with the standard recipes, so I just thought I would record the changes here. We served four recipes, preparing them well in advance and then chilling them nearer to serving time.

Base Mixture

  • Custard ……. 1 litre
  • Single Cream…… 0.6 litre
  • Icing Sugar ……. 0.25 kg

Simple Recipes

  • Ginger Galore: Base Mixture + 2 jars of Tesco Ginger Preserve
  • GoldenIce: One tin (454 g) of Golden Syrup and 3 smashed up Crunchie Bars

Variant Recipes

  • Choctopussy:  Reduces the vanilla flavour of the custard in comparison with standard base mixture, and increases the creaminess
    • Custard ……. 0.5 litre
    • Single Cream…… 0.6 litre
    • Double Cream…… 0.6 litre
    • Icing Sugar ……. 0.25 kg


  • Kir Royale: Tesco High Juice Black Currant drink, diluted 1:1 with water

Other Recipes not served

  • Rum and Raisin: Base Mixture + 200 g raisins soaked in rum (Adults only)
  • Strawberry: Base Mixture + 500 g fresh strawberries sliced thinly
  • Orange Sorbet: 1 litre orange juice + 0.25 k g Icing sugar


  • Ideally use a large  ceramic mixing bowl.
  • Put dry powders in bowl first (Cocoa, sugar) and add liquids after. Stir gently with a spoon before electric mixing. This minimises dust.
  • Mix thoroughly with an electric hand mixer. This adds air bubbles which improves quality and makes the ice cream more attractive.
  • None of the quantities involved are critical but modest accuracy helps to plan the amount of ingredients required.
  • Segregate dairy from non-dairy utensils


  • Add liquid nitrogen in 150 ml polystyrene cups. This minimises (a) the possibility of damage from accidental spills and (b) the chances of really getting the ice cream mixing dangerously cold.
  • Add liquid nitrogen to the mix while using the food mixer. With about 10 cups this is sufficient to pretty effectively chill the quantities above. The outer parts are over-chilled and the material in the centre of the bowl is still quite liquid.
  • The mixture will freeze to the outside of the bowl: Don’t worry. Keep mixing. At the end, leave for 5 minutes and scrape off the frozen stuff at the edge with a spoon.
  • If the mixture needs extra chilling, add a cup of liquid nitrogen and the stir with a wooden spoon.


  • Ensure the mixture is not too cold
  • Use clamp stands to create versatile cornet holders – saves a lot of time.
  • Serve with a scoop into a cornet. For dairy intolerant people offer the sorbet. For gluten intolerant people offer sorbet without a cornet (spoon and plastic container)
  • Segregate dairy from non-dairy utensils.
  • Wear hygienic gloves (cornet hand mainly)
  • If the mixture softens, add a little liquid nitrogen

Good Science on TV

May 19, 2011
The Oscar for Best Science Programme

The Oscar for Best Science Programme

I have been fast enough to criticise poor science programming in the past, so I feel obliged to praise good programming when I see it. And I would just like to call out four very different examples of science programmes, all of which I feel succeed. And so the nominations for the Oscar for Best Science Programme are:

 Inside The Human Body is a 4-part series about the human body. It has a presenter (Michael Mosley) who is eloquent, opinionated, clearly flawed in many ways, and obviously knowledgeable. Each programme simplifies the story, focussing on perhaps 5 key themes in the one hour slot. Repetition of graphical material is subtle, leaving one feeling grateful rather than bored., and live material often focuses on named individuals and borders on the prurient, but generally stays focussed on the topic at hand. And centrally it is gloriously enthusiastic about all that being human involves.

Bang Goes the Theory  is a 30-minute popular science magazine programme shown at 7:30 p.m. on BBC1. It is hosted  by a pretty boy, a pretty girl, an apparent geek and the genius Jem Stansfield who is the actual star of the show. If you asked my children they would tell you that I shout at the TV during these shows, but the truth is: this programme is not made for me! And I admire its ability to present real scientific topics in prime time  and still make it to series 2 – and now series 4!

Science on Science is a new magazine programme on Discovery Science and so is under considerably less pressure to keep an audience than Bang Goes The Theory. The hour is divided into typically four segments which are narrated but we never see the narrator. The characters are the scientists and engineers who present their own work through the frosted glass that is the modern style of  television presentation. Seeing the actual scientists and engineers brings this programme alive and makes it more ‘real’ than many of the presenter focussed shows.

Mythbusters is now in its gallizionth series and has gone global. The two presenters Adam and Jamie were special effects designers before creating this programme, and they use their very practical skills and scientific intuition to design and build experiments to test urban myths.

  • Goldfinger Movie Myth: Do you suffocate if painted all over in gold paint? Glorious Jamie was painted and – with paramedics attending – he did not suffer at all.
  • Poppyseed drugs test myth: Do you test positive for heroin if you eat a poppyseed muffin? Amazingly, you do!
  • Cement Mixer Myth: Can you use dynamite to clean out the inside of a cement mixer in which the cement has solidified? No, not without evaporating the cement mixer.
From a scientifically pedagogical point of view, this programme is flawed because they rarely make any calculations. But in televisual terms, this programme is golddust and encapsulates the joy and pleasure and occasional pain of experimental science. It is just great TV.

And the winner is… we all are. These programmes all make you want to stop watching and … well DO something. These programmes all bring the genuine joy of discovery and understanding into people’s lives, and for this I am genuinely grateful to them all.

Global Warning of Global Warming

May 19, 2011
Svante Arrhenius

Svante Arrhenius

An extract from The Scientific American, June 1911

Svante Arrhenius has advanced an ingenious theory to account for the glacial periods which have marked several stages of geological history. According to the experiments of Langley, the carbon dioxide and the water vapor which the atmosphere contains, are more opaque to heat rays of great wave lengths which are emitted by the Earth, than to waves of various lengths which emanate from the Sun. Arrhenius infers that any increase in the proportion of carbon dioxide and water vapour in the atmosphere will increase the protection of the Earth against cooling and will consequently raise the temperature of its surface. The theory assumes that the Earth’s atmosphere was poor in carbon dioxide and water vapour during the Earth’s cool glacial periods, and rich in these gases during the hot periods.

Arrhenius’ prescience and insight make me feel humble. I would like to end with something clever or funny, but in fact I am stunned and I think I will just stop here.

The power of water

May 18, 2011
US Army Corp of Engineers Photograph of the Morganza Spillway.

US Army Corp of Engineers Photograph of the Morganza Spillway.

If you ask my advice, there is nothing as nice, as messing about on the river“. And humans have felt that way for a long time. Our settlements have followed river valleys from the mountains out to the sea since the dawn of time. But when the water – either from the river or the sea – wants to be where we happen to live, there is generally only one winner. When disaster strikes people are wont to say that it was unpredictable. However in almost all cases, exactly the opposite is true. These disasters are in fact entirely predictable –  it is just that we have short collective memories. So for example:

  • The tsunami which hit Japan earlier this year , was really only a one-in-one-hundred-year event. How could people have collectively ‘forgotten’ that the sea did this?
  • The flooding in Brisbane last year was entirely predictable, and had happened previously as recently as 1974.
  • Hurricane Katrina’s terrible toll in New Orleans, is really quite understandable in a city which is built below sea level!

And in the face of these disasters I have been extremely impressed by the US handling of the current flooding on the Mississippi – summarised in this Washington Post graphic. The authorities have followed the floods and predicted the extent of the flooding downstream several days in advance. They have destroyed levees to flood farm land rather than cities, and finally opened the splendidly-named Morganza Spillway to successfully prevent flooding in New Orleans. 

The Morganza spillway was envisioned  after the great flooding of 1927, and completed in 1954 in the sure and certain knowledge that at some time in the future there would be another flood that might widen the river to 80 miles across in places. If the Thames flooded like that it would nearly reach the south coast. What I admire is the collective political and engineering understanding that built and maintained this structure through all these years in which it wasn’t needed: it was last opened in 1973. The actions of the engineers have turned flooding from a catastrophe causing loss of life and distressing rescue, into a predictable disaster – the flooding of the surrounding farmlands has been completely predictable giving people many days notice, and allowing them to leave their homes safely.

Reading about the smart flood management, I allowed myself to imagine that the collective might of the US Army Corp of Engineers might deployed to, say, Bangladesh or Pakistan, to wage a ‘War on Water’. Imagine if they constructed dams and levees to protect the country from sea flooding in case of sea level rise. And created designated  flooding areas to manage floods from extreme rains or melting. It might cost a few billion dollars, but the benefits would last for a century or more. Giving people plenty of time to do all the things we love to do by the riverside.

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