Archive for May, 2011

The Atom Splitter: Ernest Walton


In 1932, aged 29, Waterford-born Ernest Walton, pictured here on the right, did something remarkable – he split the atom, or the atomic nucleus to be more precise, and the news stunned the world.
This colossal event in the history of science took place in Cambridge, UK, in the Cavendish Laboratory, a world-famous laboratory run by Lord Ernest Rutherford, a New Zealander. Rutherford had won a Nobel Prize for physics in 1908 and was a huge figure in science in general and nuclear physics in particular.
Walton, meanwhile, was a brilliant apparatus man, a hands-on physicist, and he had personally built the particle accelerator machine that enabled the nucleus to be split. He worked closely with John Cockcroft, who was a theoretician. They were a perfect team. Cockcroft proved it could be done, and Walton then went and did it.

Newspapers around the world reported the news, and the Albert Einstein himself called to the Cavendish Lab to congratulate Walton and Cockcroft.

For Einstein, this experiment was the first solid evidence to support his famous equation e = mc2 which held that energy and mass were linked, and that it was possible to release enormous amounts of energy – if mass could be split apart.

EXPERIMENT 
The key to the success of the famous atom splitting experiment was perhaps the inspired decision by Lord Rutherford, Head of the Cavendish, to pair the hands-on Walton, with the theoretician Cockcroft.

Rutherford, recognised the talents of the two young geniuses at his disposal, and put them together. They were very different, but complimented each other.

At this time, The Cavendish and other labs, particularly in the US were in a race to see who could split the atomic nucleus first. The general thinking at the time was that particles, protons would need to be accelerated to very high speeds, at astronomically high electrical voltages – perhaps as high as one million volts – to make it possible for them to slam into atomic nuclei and split them.

Walton had done his PhD in the generation of high voltages and this was a continuation of that work. He got the voltage up towards 800,000 volts and they decided they would try and experiment and see what happened.

Walton got the machine going and crawled back across the floor of the lab towards a lead-roofed observation box – to protect against x-rays and high voltages. The protons were being slammed into a piece of lithium metal and he took at look now at the impact. He immediately began seeing little flashes.

He was elated, as the flashes, he knew could be an indication that the lithium atoms were being split into two helium nuclei, also known as ‘alpha particles’ which had been first discovered by Rutherford himself three decades earlier. Walton immediately called Cockcroft to come, he knew something was happening. He later described what looked like ‘twinkling stars’ – lots of them.

Cockcroft arrived, and Rutherford then appeared. The two younger men manoeuvred Rutherford into the small observation hut, which wasn’t easy, as he was a big man, it was a tight space, and, at this stage, the great man, wasn’t young either.

Philip, Ernest’s son, and himself a Professor of Physics at NUI Galway (recently retired) recalled what his father told him happened next. “He (Rutherford) was shouting out instructions – ‘turn up the voltage’, ‘turn down the voltage’ and whatnot. He got out, and without saying anything at first, he walked across the room, perched himself on a stool and said: “Those look mighty like alpha particles to me – I should know, as I was in at their birth.”

The atomic age had begun.

FIGURE 
Walton was an unlikely figure to be thrown into the media maelstrom that occurred after the 1932 experiment. It changed his life forever, and at a time when most scientists are only getting their careers started he had reached his pinnacle.

He was a strongly religious man all his life –  the son of a Methodist preacher who had travelled all over Ireland and lived in many towns on both sides of the border, including Cookstown, Bambridge, Dungarvan, Armagh and Drogheda.

Sunday’s were for religious service and nothing more, whereas every other day was all about work. He was also a non-drinker, with a few close, loyal friends.

He had attended Methodist College in Belfast as a border, where he was ‘Head Boy’ and he had developed a strong affection, which was returned for the school’s ‘Head Girl’, Breda. After they left school they went their separate ways, but after a chance meeting the relationship was re-ignited and the letters flew back and forth.

He returned to Ireland in 1934, not least because he wanted to marry Breda, who was working as a teacher in Waterford. They were duly married in Dublin, and set about raising a family from their home in St Kevin’s Park, in Dartry, Dublin 6.

Walton returned from Cambridge to head up an ailing Physics department, with just three staff. His workload was huge in terms of administration, and teaching. This all mean that from the time he returned Ireland, to TCD, he did little research.

He died in 1995, aged 92, and is remembered fondly by his colleagues and family as a quiet man, who had no interest in the limelight. Often he would sit in the staff room at TCD quietly humming a tune, when a visitor would come in, and be stunned to be introduced to Ernest Walton, the giant of Physics that split the atom.

Many students will remember him as a brilliant teacher, who often performed experiments on the bench, in front of the students during a physics lecture. His son Philip, the recently retired Professor of Physics at NUI Galway, recalls that his father spent many long hours in the attic at home, after dinner, preparing his lectures.

Others will remember him at the Young Scientist Exhibition in the RDS for many years, when he could be found in teacher mode surrounded by an enraptured audience. For ETS Walton, teaching was a very important part of the scientist’s job.

To this day he remains the only Irishman who has been awarded a Nobel Prize in any field of science. That was in 1951, 22 years after the atomic nuclei was split.

This article was first published in the May-June issue of Science Spin

How Irish Scientists Changed the World, by Seán Duke, is due for publication by Londubh Books in 2012.

What attracts people to a career in science?


Laura Brennan and Megan Oliver, pictured here, Transition Year students at Dominican College Drumcondra, wanted to discover the factors that attract and turn people off to science as a career. 

Why do some people want to become scientists, while others avoid science subjects in school at all costs?

Laura Brennan and Megan Oliver, Transition Year students at Dominican College Drumcondra, north Dublin, sought some answers to these important questions.

Both Laura and Megan are keen on science, and come from a school that is keen on science, judging by the number of projects at the BT Show in January this year from Dominican College. They are also at a crucial juncture in education, as they are about to enter the Leaving Cert cycle and need to make subject choices that will influence their careers.

The girls are ideally placed to judge what it is they like about science, what it is that others don’t like about science, and how can science be made a more attractive option for students at secondary level. The government should pay attention to their findings.

‘NERDY’

The first thing they are keen to ‘put to bed’ is the notion that teenagers are turned off science because of the perception that it is ‘nerdy’ and not something for the ‘cool’ set. They found, in their survey of their peers, that 80 per cent plus were not in the least put off by the perception of science as nerdy. One urban myth shattered then.

The reasons that science is not attractive to many, they believe, have more to do with the perception among some students that science is not relevant to their daily lives. For example, the students said, the group of students disaffected with science, don’t see why an understanding of the atom and its parts, has any relevance to their lives.

Another problem is that science is perceived as being hard, and that it is hard to get into university to study science subjects. This perception doesn’t stand up, said Laura and Megan, and they compared journalism and science at DCU. In 2010, they said, it took about 375 points to get in to study on a science course, while the journalism course was far more difficult to get into with, as it required 445 points. If people knew that it wasn’t so hard to get in to science in college, more might aim for it they said.

It was once the case that girls’ schools didn’t do science subjects, or perhaps only biology, and while things have changed in recent years, things are still not ideal for girls interested in science. They said there was not technology or technical graphics on offer at their school, while both were available at the boys’ school up the road. A lot more girls would be interested in technology than home economics, they said.

Ireland can learn from other countries in the teaching of science, the girls believe. For example, in Sweden, students have 800 hours of taught science per year, whereas Irish students do 600 hours. That extra exposure makes a big difference, the girls believe.

It is vital, the girls believe, that greater effort is made to spark an interest in science, and how the world works generally in students at a young age, before secondary school. For example, they said, people like to know how things work, so perhaps one way for primary teachers to ignite an interest in science would be to take things apart, such as a clock, and demonstrate how the pieces interact to make the clock tell time.

Also, it is important that students are taken out of the classroom situation more, and shown how science is relevant to their lives. For example, a trip to a science museum, or some other place could demonstrate the importance of science to all of us, they say.

The girls have some specific suggestions to increase the numbers of people taking science subjects at second level, as well as wanting to do science as a career.

Some suggestions from the students to encourage more people to aim for a career in science:

  • Science should be mandatory up to the Junior Certificate. At the moment it is possible for students to pass through secondary school without doing any science whatsoever.
  • There should be less Biology and more Physics and Chemistry on the Junior Certificate curriculum to encourage more interest in the latter two subjects.
  • There should be at least one 40 minute class per week dedicated to understanding the mathematics behind a scientific concept, and vice versa.
  • There should be less emphasis on rote learning and more on understanding.
  • Girls should be encouraged to take science subjects, and especially honours maths as many might still not be confident enough to sign up for these subjects.

West Cork students put green, slimy invaders to good use


The beautiful beaches of west County Cork have sadly, in the past few years, been overwhelmed by hordes of unwelcome, green, slimy, smelly, and noxious invaders.

No, this story has nothing to do with certain human visitors to the area. Rather this concerns the arrival of a green algae, ‘Sea Lettuce’ – or Ulva Lactuca to be precise.

It is not clear why the Sea Lettuce has arrived in rural Cork in such numbers. The two most popular theories are that it has something to do with global warming, as the Sea Lettuce is a creature that thrives in shallow, warm waters, or that it is linked to the pressure put on the local waste water plant.

It’s said that the Clonakilty waste treatment plant can’t cope with the increase in holiday homes in the area in recent times.  The inevitable result, it is argued, is the leaking of raw sewage into the ‘run off’ water, upon which the Sea Lettuce thrives.

But, no one knows the exact cause for sure.

Neither is west Cork alone, as this is a global problem now, one that has reared its head in places as far flung as Brittany, Beijing and Australia.

SLIME

The local people in Cork have watched in horror as their beautiful beaches have disappeared under piles of green slime, sitting on top of the sand, emitting noxious gases and killing off some existing forms of sea life.

Enter three enterprising local Transition Year students, Muireasa Carroll, Mairéad Kingston and Denise Hurley, pictured above, from the Sacred Heart School in Clonakilty. They wanted to see if they could turn a ‘negative into a positive’.

They come up with a great idea. To harvest the Lettuce, use a machine to compress the water out of it, and mould it into briquettes for burning. They would then see if the Lettuce briquettes were a viable source of heat, and what gases they would emit.

They made their briquettes using a hydraulic pumping ramp. They tested the briquettes and found that they burned slightly longer than peat, with slightly less heat emitted. Also, the briquettes were ‘carbon neutral’. That meant that, unlike fossil fuel briquettes, they did not emit significant amounts of carbon dioxide ‘greenhouse gas’.

They appeared to have a viable ‘renewable fuel’ product that could be harvested cheaply from the strangled beaches in their locality. But, they didn’t stop there. They tested the briquettes for water concentration and found that even after they were compressed and moulded that the briquettes were made up of 25 per cent water.

If they can eliminate more water, they will have a product that burns even longer.

They also looked at the waste products from the burning of the briquettes – ash – to see if it could be put to good use. They found that the briquette ash was a very effective fertiliser and that it was also useful as a cleaning product to absorb stains.

All in all, it’s a brilliant idea, and reflects the move in recent years at the BT Young Scientist and Technology Exhibition discoveries that can help society to improve. Certainly, Sean Gallagher, one of the ‘Dragons’ from the RTE series ‘Dragons Den’ thought it was an excellent idea when he stopped to have a look while at the Show.

The girls are veterans of the Show and were also at the RDS in 2010. They impressed then too, enough to be offered a marketing course at TCD, which they took.

The Lettuce briquettes have been registered as a patent with the Irish patent office, and the girls want to develop the product into a business at some stage in the future.

They have also been invited to talk to local county councils, about their great idea.

But, for now, they have the Leaving Cert to attend to, but watch this space, this is an idea that could ‘find legs’ when the girls emerge from school in a few years time.

This project was the winner of the ‘Intel Students of Excellence Award, at the BT Young Scientist and Technology Exhibition 2011.

This article was first published in Science Spin (May-June 2011 Issue)

Super-Powerful Telescopes, the ‘Misunderstood Crocodile’


The European Extremely Large Telescope, shown here as an artist’s impression, due to be built in 2018, could answer some of the Universe’s unanswered questions (Credit: European Space Observatory)

Science Spinning: ‘The Show with an Irish Spin on Science’, Presented and Produced by Seán Duke

Super-Powerful Telescopes, the ‘Misunderstood Crocodile’

This episode was broadcast on Dublin City FM, 21/04/2011

To contact the show email: sciencespinning@dublincityfm.ie

Follow

Get every new post delivered to your Inbox.

Join 806 other followers

%d bloggers like this: