February 2010

FEATURES

It's the WINE TALKING

by Leslie J. Brinton of 'In the Pink' 01986 872579

Many of the wines made from the Gamay grape, especially in the Beaujolais region, are designed for drinking in their extreme youth.

Some of the finer bottles do however benefit from a bit of age and those sourced in the commune of Morgon are among them.

One bottle which has started its drinking life and which I commend for February sipping is from Domaine Brisson: at just 12.5% alcohol and with light cherry flavours on the palate, it offers a lot of pleasure already. Look for Morgon Les Charmes 2007 at the Co-op, slightly underpriced at £7.99.


Leslie J Brinton

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This is the latest in a series of articles on stellar and tidal phenomena written especially for the Organ by astrophysicist, Prof. Michael Rowan-Robinson

Coriolis force, North Sea tides and draining bath tubs

My friend and neighbour, Peter Fells, asked me about a demonstration he saw in Equador, on the line marking the equator itself. A portable basin of water was drained first on one side of the line and then on the other. The water swirled out in opposite directions on the two sides of the equator, allegedly due to the Coriolis effect.

In a treatise on hydrodynamics in1835, the French scientist Gaspard-Gustave Coriolis discussed an effect of the rotating earth that has become known as the Coriolis force. In fact the great Pierre-Simon Laplace had discussed this same effect more than 50 years earlier, in his work on tides of 1778. In a non-rotating (‘inertial’) frame of reference a moving projectile or particle of fluid with no forces acting on it will travel in a straight line, but if we observe it in a rotating frame the path will appear curved. If two children on opposite sides of a spinning roundabout throw a ball to each other, it will appear to them to follow a curve path. Gunners on the battleships of the First World War had to correct for this effect when aiming their guns. Mathematically the effect can be modelled by postulating a force that depends on the velocity of the projectile, the rotation rate of the frame, and the angle between the rotation axis and the direction of motion.

The most dramatic effect of the Coriolis force is in large-scale weather systems. Air travelling from regions of high to low pressure deviates to the right in the northern hemisphere and to the left in the south. As a result, low-pressure systems are surrounded by cyclonic winds, anti-clockwise in the north and clockwise in the south. The most violent systems, originating in the tropics, are called hurricanes in the north and typhoons in the south. Conrad describes the amazing central stillness of these systems in his short story Typhoon.

On the East Coast we see another dramatic effect of the Coriolis force, the amphidromic circulation of the North Sea. Superposed on the daily tidal motions, there is a general anti-clockwise circulation of the North Sea, which results in the sequence of high and low times going Yarmouth, Lowestoft, Southwold, Aldeburgh, Harwich, Southend, Ramsgate, Dover, and then up the other side of the North Sea, Ostend, the Hook, Groningen. This circulation is at least partially responsible for the ‘southward drift’ of eroded material, building up the shingle bank at Shingle Street and also the string of islands to the northeast of Holland, stretching from Den Helder to Wilhemshaven.

In Stars’n Tides 4, I flippantly described the Coriolis force as “the force which tends to make bath water go down the plug-hole in an anti-clockwise direction in the northern hemisphere”. In fact the Coriolis force is far too weak to affect the motion of water in your bath, by a factor of thousands. The effect has been demonstrated in very large symmetrical tanks of water left to settle for more than 24 hours before carefully removing a centrally placed plug.

A scam very similar to the one described by Peter Fells is aimed at tourists in Nankuyi, Kenya, on the equator, and was shown on Michael Palin’s Pole to Pole BBC programme. A sink of water is shown draining with circulation in one direction on one side of the equator line and in the opposite direction on the other side of the line. In fact, quite apart from being much to weak to affect anything, the direction of the Coriolis force is vertical on the equator so cannot affect the direction in which water drains out of a basin.

Stars’n Tides now has an email address for you to send comments and queries: starsntides@southwoldorgan.com

Past Stars’n Tides articles can be found at http://astro.ic.ac.uk/~mrr/starsntides/

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Stamping around
Picture the scene. The Royal Mail marketing team, philatelic advisors and assorted other bods sitting around a meeting table, flipchart at one end, tea and coffee at the other. The agenda for the meeting is special stamps for 2010 and, after reviewing minutes of the previous meeting, apologies for absence, review of 2009, they’ve eventually reached item five on the agenda, February 2010, and agreed that it would be a good idea to celebrate the 350th anniversary of the Royal Society. That’s when the fun starts. Some of the committee want colourful stamps, some of them want portraits of significant members of the Royal Society and some want pictures representing the Society’s contribution to science. The debate goes on for so long that they fail to complete the schedule of stamps for the year ahead and agree a compromise for February.

The result is a set of ten First-Class stamps, each with two images – one with a black-and-white portrait and one with a colourful image depicting the work of the scientist in the portrait. The top of their heads and their chins have been cropped, allowing us a glimpse of eyes noses and mouths of the distinguished scientists. Ten stamps, neither one thing nor the other.

Whilst there may be some household names here, I challenge you to recognise the faces of Sir Isaac Newton, Benjamin Franklin or Edward Jenner. Harder still, would you know Robert Boyle, Charles Babbage, Alfred Russel Wallace, Joseph Lister, Ernest Rutherford or Sir Nicholas Shackleton? There is a chance that somebody may recognise Dorothy Hodgkin, who attended Sir John Leman School in 1921. She went on develop protein crystallography and was the first female Briton to win a Nobel Prize. Science teaching must have been their forte in the 1920s.

The Royal Society stamps are available from 25th February. On 2nd February, a mini-sheet will be available celebrating the centenary of the Guiding movement. This mini-sheet has four stamps covering the four age groups in the Girlguiding group – Rainbows, Brownies, Guides and Senior Section – showing some of the activities that the groups undertake. What a shame that these contemporary stamps are not available as ordinary stamps instead of a mini-sheet, while the Royal Society gets preferential treatment.
Guy Mitchell, Spots

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View to the north
January has been a month of marked contrasts, strong winds, rain, many consecutive grey days, bright blue skies and, of course, the snow.

The cold snap has brought a number of birds into the gardens and onto Town Farm Marsh. This is the area to the immediate north of North Road which was named after the farm which was located close to the hospital in Field Stile Road. This can be seen in a 1938 map of the North Road area.

The appearance of Redwings reminded me that I have not seen thrushes for many years. A few years back they used to collect snails from the marsh and use my front door step as an anvil. Coincidentally towards the end of January a thrush appeared in the garden, a most welcome newcomer. Equally pleasing are the flocks of long-tailed tits that appear in an instant, feed furiously and then disappear as rapidly as they arrive.

The fields north have the usual flocks of Barnacle Geese and occasionally the much smaller Red Breasted Goose can be seen. Greylags, more plentiful in the summer, have also been spotted on a less regular basis together with 3 Brent Geese. Smaller wildfowl include the very common mallards, the beautiful teal with the golden triangle on their flank, gadwall and shoveller ducks. Snipe have been seen sheltering from the cold and the long curved bill of a curlew as it flew over. A little egret has returned on a few occasions and it has been interesting to see the heron perch on neighbours’ roofs, presumably looking for ponds for an easy goldfish or two. One other strange sight was a pheasant that had made its way into my small back garden. It was on top of the hedge trying to eat seed from the caged feeder that is really only suitable for the blue tits, great tits and coal tits that frequent the area.

About 2 inches of rain has fallen during the month which has made a great improvement to the water levels in the boating lake, which was frozen over during the cold period. The high winds and high tides have made an impact on the beach. Just after the start of the New Year it was very difficult to walk up the beach under Easton Bavents to Covehithe. The beach levels have now risen but a large amount of cliff has been lost close to the first dip to the north.

Only a few years ago this was banked up as was the area around Easton Broad. However this area where the geese can be seen overnight is under continual threat from the sea and I am sure that we will see more flooding in the future on the road to Wrentham around Potters Bridge. The beach erosion was also very obvious immediately to the north of the promenade where the old wooden timbers were exposed.

When fishing was far more prevalent and before the sea wall was built the area of the current car park and to the north was a village of fishing huts. Presumably the timbers are remnants from the foreshore of the old fishing community.

Halcyon
halcyon@southwold-northroad.com
www.southwold-northroad.com

 

 

 

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