Science

Pylon of the Month - February 2016

AndromedaPylon

A long time ago in a galaxy far far away, some photons of light set out on a journey towards earth. They arrived recently and had the luck to be captured by @Skullet who posted a picture on twitter which caught my eye because of the pylon.  The galaxy concerned is Andromeda and you can see it near the top of the picture above the pylon as a smudge of light.  It's 2.5 million light years from earth which means that the photons of light were traveling through space for 2.5 million years (at about 9500 billion kilometres per year, that is definitely far far away). Andromeda is a galaxy in our local group and because it is visible with the naked eye (if you are in a suitably dark place) it has been known about for a long time.   Wikipedia has this to say

The Persian astronomer Abd al-Rahman al-Sufi wrote a line about the chained constellation in his Book of Fixed Stars around 964, describing the Andromeda Galaxy as a "small cloud".  Star charts of that period labeled it as the Little Cloud.[19] The first description of the Andromeda Galaxy based on telescopic observation was given by German astronomer Simon Marius on December 15, 1612.  Charles Messier catalogued Andromeda as object M31 in 1764 and incorrectly credited Marius as the discoverer despite it being visible to the naked eye. In 1785, the astronomer William Herschel noted a faint reddish hue in the core region of M31. He believed M31 to be the nearest of all the "great nebulae" and based on the color and magnitude of the nebula, he incorrectly guessed that it is no more than 2,000 times the distance of Sirius.  In 1850 William Parsons, 3rd Earl of Rosse, saw and made the first drawing of Andromeda's spiral structure.

Back down to earth, the pylon itself is near Crianlarich in Scotland.  Pylon fans interested in visiting the area will be delighted to know that there is plenty to do in the local area, especially if hill walking is your thing.  The last time I was there was about 26 years ago when walking the West Highland Way (with a quick diversion up Ben More on the shores of Loch Lomond) but perhaps this is the excuse I need to revisit the area! Pylons are actually quite a contentious issue in parts of Scotland at the moment with Dumfries and Galloway being especially concerned;  http://dumgalagainstpylons.org/.  As is often the case, it mainly comes down to whether or not one thinks that the additional cost of burying and then maintaining underground cables is justified when weighed against the impact of large pylons on the landscape. It is a problem that isn't going to go away because of the drive for more renewable energy. Getting the electricity from where it is generated to where it is needed means transmission lines and pylons are the cheapest way of doing this, at least if you are thinking only in financial terms.  The relative costs of the overground versus the underground option are much debated as this 2012 report shows and it is not a straightforward issue.

So there you go; it was already late February when this pylon was posted. I hope it was worth the wait and that you've learnt something if you've read this far.


Pylon of the Month - July 2015

Pylon

 

With my summer holiday (in Turkey) looming and the usual 'holiday pylon' to follow in August, I thought that I would choose a UK pylon for July.  I have quite a backlog of submissions from fans of the website, but this rather splendid one from Essex caught me eye as I trawled back through my collection of emails from the last year or so.  This is what the email I received had to say:

I recently took these photos whilst out on a 10 mile hike near Woodham Ferrers which is near Maldon in Essex.  I thought the pylons were majestic and fascinating, hence looking on the web at other photos and coming across your site.

Woodham Ferrers itself has more than a few points of interest of which my favourite is that it was attacked during the Peasants' Revolt in 1381. This revolt, about which I knew almost nothing (the name Wat Tyler rang a bell, but that was about it.....), seems to have been about a form of Poll Tax and started in Essex and then spread to Kent.  

I recognised the name of Maldon because of the sea salt connection.  It has been harvested since 1882 because Flat tide-washed marshes and low rainfall mean high salinity.  So pylon fans heading to Essex can top up on sea salt and this series of email exchanges on whether there is a discernible difference between sea salt and other forms of salt makes for interesting reading before you make any purchases.  For literature fans, Maldon also features in HG Wells's War of the Worlds and in the Marvel Universe, the twin superheroes Psylocke and Captain Britain were born and raised in Maldon.  Science fans will be equally pleased to know that John Strutt, 3rd Baron Rayleigh, was nor in Maldon and went on to win the Nobel Prize in physics in 1904 for:

...his investigations of the densities of the most important gases and for his discovery of argon in connection with these studies".

Perhaps more relevant to the picture above, the reason for the blue sky in the background is due to Rayleigh scattering.  I'll end on that note and if you have read this far, then I hope that you are as delighted as I am that a pylon picture can lead to so many interesting (if somewhat random) facts about Essex.  I'm always better informed after writing these posts and hope that any readers are as well.


Pylon of the Month - June 2013

IMG_1394
This month's pylon comes from Kennington just outside Oxford and for reasons that will become obvious, I took it myself very recently.  It is very easy to find, being a few hundred metres from Sandford Lock on the Thames on the Sustrans cycle path from Abingdon to Oxford.  But the main reason I chose this pylon is because I could get a close up of something attached to the wires just before cables join the tower. Once you have seen the in the picture below, you will see them everywhere, but unless you are a real pylon spotter you have probably never noticed them before.

IMG_1393
The objects in question are the dumbell shaped objects and they are known as Stockbridge dampers or dog bone dampers because of their shape.  They perform a vital role in preventing damage to the cables and in order to explain how they work, it is time for a little bit of theory.  Some readers of the blog might know that I am a Physics teacher, but I will try to stop myself from getting too carried away.  I'll also try to get the physics right without over complicating or over simplyfying things, which might not be as easy as it sounds.

The basic problem is that wind blowing on the cables can make them vibrate, or more specifically vortex shedding on the leeward side leads to this undesirable effect.  It can do this in a number of ways, but one of the modes of oscillation is called Aeolion vibration or flutter.  The vibration has an amplitude of a few millimetres to a few centimetres (this is how far the cable moves up and down) and a frequency of anywhere between 3 - 150 Hertz (vibrations per second).  This kind of effect, where some a driving force (in this case the wind) causes something to vibrate at its natural frequency is very common.  If you have ever seen or heard a washing maching as the drum speeds up in the spin cycle, you might have noticed that there is at least one particular speed where the washing machine shakes violently.  The problems with the Millenium Bridge in London when it wobbled as people walked across it just after opening were also a variation on this theme. But the most dramatic example involving the wind is probably the collapse of the Tacoma Narrows Bridge and if you haven't seen a video of the wind induced oscillations, now would be a good time to tick that off your 'things to do before you die' list.  But back to pylons, because as you will know if you have ever bent a paperclip a few times, repeated stress can lead lead to the metal failing and in the case of pylons on a windy day (or more likely the cumulative effect of many windy days) this could lead to strands of the overhead power lines breaking.

So how do Stockbridge dampers help?  In very simple terms, instead of the wire vibrating the masses on the end of the damper vibrate instead and so the cable vibrations are 'damped' or reduced in amplitude. The idea was invented by George H. Stocbridge in the 1920s and originally consisted of two small blocks of concrete on the end of a piece of metal wire.  

250px-Stockbridge_patent_closeup

The original US patent is an interesting read if you want to know more, but in the words of the inventor:

My invention relates to means for preventing objectionable vibration in suspended cables, such as are used in electrical transmission lines and the like.....

The wikipedia page on Stockbridge dampers also has more information, but there is much that I would like to find out about how they are used.  In particular, are all dampers the same or do they vary depending upon the specification of the cable?  If you work for National Grid and know the answer please do get in touch and if you had a real life Stockbridge damper that I could use when teaching about resonance in my Physics lessons, I would be extremely grateful.

If this was all a bit too much information for the casual visitor to the website just looking for a new pylon picture then I can only apologise.  I hope that you can at least spot a few Stockbridge dampers on your pylon travels and if nothing else, it might make you realise that there is more to pylons than meets the eye.


Pylon of the Month - June 2012

Pylon

I have a backlog of pylon pictures sent in by fans from all over the world.  I try to mix them up with pylon pictures from the UK so that the blog doesn't lose touch with its roots, but as soon as this image arrived in my inbox I knew it had to be the June 2012 pylon. Why? Because the three bright dots in the sky above the pylon are the moon, Saturn and Jupiter.  This month sees the last transit of Venus until December 2117 and so an astronomical themed pylon seemed very appropriate.  I think (not knowing exactly when the photo was taken) that Venus is the lower of the two planets (pretty much alongside the moon) and it really is worth clicking on the image to enlarge it and see it in all its glory.  For more on the transit (and if you are a keen follower of astronomy you have probably had enough by now) then this Cocktail Party Physics blog post is a good place to start.  I got up at sunrise (0450ish) on the 6th June and the clouds cleared at about 0530 and so I saw the last 20 minutes which was made the early start well worth it.  

But now to more pylon focused matters.  This month's picture was taken in Ballyfermot, a suburb of Dublin. If you look carefully you will see that some of the arms of the pylon don't have wires attached because they were still under construction as the photo was taken.  I'm not sure what the pylons are being built for, but it gives me an opportunity to talk about the plans to link up the Irish and British electricity grids.  Britain is an importer of electricity from numerous sources. One of these sources is Northern Ireland via the Moyle Interconnector, although that was broken last year and is still not up and running again as far as I can see.  There are also links to the Netherlands and France and if you have an ipad or ipod you can see live data via this app about where the electricity is being generated at any given moment.  But the new link under construction is to run from Rush North Beach in County Dublin to Barkby Beach in North Wales and is known as the East-West interconnector.  For the benefits of the project as seen by the company building it, look here.  Interestingly, the Guardian last year had an article about the possibility of wind farms on the West coast of Ireland being linked to the UK by another interconnector but given the impact of large numbers of wind turbines on the beatiful coast of Dingle and Kerry, whether this project goes any further is very much open to debate.

So from astronomy to the West coast of Ireland via the UK's imported electricity supply. Another month where Pylon of the Month provides information on subjects that you probably had no idea could be linked together.  Come back next month for more!


Pylon of the Month - January 2011

DSCF0472

Happy New Year to pylon fans everywhere.  After a Christmas break where I failed to get any pylon pictures with accompanying snow and ice I decided to start 2011 with this rather marvellous image taken by a pylon fan very close to Radley, a few miles outside Oxford.  

I like it on a purely visual level and if all you want from Pylon of the Month is a chance to look at pictures of pylons then you might want to stop reading now. ......

because the picture could also be seen as a metaphor for what some see as the battle between science and the arts.  I probably need to explain in a little more detail!  As I discussed in a recent post, pylons are frequently seen as the all to obvious symbols of technology riding roughshod over aesthetic and environmental concerns.  It was Keats who first used the rainbow in the argument between the arts and science when he accused Newton of destroying its beauty by explaining it.  It inspired Richard Dawkins to write 'Unweaving the Rainbow' which argues that understanding actually enhances our appreciation of the beauty rather than destroying it and I'm with him on this one.  Richard Feynman, one of my scientific heroes, also had this to say on the subject:

Poets say science takes away from the beauty of the stars — mere globs of gas atoms. Nothing is "mere". I too can see the stars on a desert night, and feel them. But do I see less or more? The vastness of the heavens stretches my imagination — stuck on this carousel my little eye can catch one-million-year-old light. A vast pattern — of which I am a part... What is the pattern or the meaning or the why? It does not do harm to the mystery to know a little more about it. For far more marvelous is the truth than any artists of the past imagined it. Why do the poets of the present not speak of it? What men are poets who can speak of Jupiter if he were a man, but if he is an immense spinning sphere of methane and ammonia must be silent?

So if you want to appreciate this month's pylon picture on a deeper level, then for more on the origin and background to Keat's comments, I can't recommend Richard Holme's book, 'The Age of Wonder' too highly.  Prior to this book, he was better known as a biographer of Romantic poets but this is an excellent account of the close interplay between science and the arts in the 18th and early 19th centuries.  For an account of the physics behind rainbows, here would be a good starting point.