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Archives for January 2010

Why is the Atacama Desert so dry?

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Guest blogger | 10:22 UK time, Thursday, 28 January 2010

I am sure that is a question which Mark often asked himself as he cycled the length of the Atacama Desert back in December. You can see where Mark is right now, and what he got 'up to' after the desert cycle on ´óÏó´«Ã½ Cycling The Americas.

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The occupies the northern part of Chile and small parts of the neighbouring countries of Peru, Bolivia and Argentina. It is approximately 1000 kilometers in length and about 150 kilometers at its widest. It is the driest desert on earth with some places having never recorded rainfall. This photo shows Mark in the town of Quillagua in northern Chile sitting beside a local resident who has never experienced rain falling. I guess umbrellas don't sell well in Quillagua!

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Deserts are described as places receiving less than an average of 250 mm of rain in a year. The Atacama, however, receives less than an average of 1mm a year! This often means that decades pass without any rain at all and then one brief rain storm brings just a few millimeters. The deserts of south west USA and northern Mexico that Mark cycled through in the early autumn are positively 'wet' by comparison.

Why is it that amongst the world's dry places, the Atacama is the driest of them all? The simple answer is that is doesn't rain there. So why doesn't it rain? If we can answer that question, we can explain why the Atacama is the driest desert on earth.

There are basically three reasons why an area may be a desert. Any one of those reasons is enough to cause desert conditions but the Atacama has all three! The diagram below shows how these affect the Atacama.

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Firstly the Atacama lies on the wrong side of the Andes with regard to the prevailing winds. At 20 degrees south the most common winds are the south east trade winds which carry in moist air from the Atlantic. As the winds are forced to rise to cross the Andes, they are cooled (remember it gets colder the higher up you go). Eventually, the moisture in the air condenses and turns to rain, falling on... the 'wrong' side of the Andes! This means that the Atacama lies in a rainshadow.

The second reason is a little harder to understand but is related to air pressure. Air generally rises at the equator because this is where maximum heating of the earth's surface occurs. Once it rises into the upper atmosphere, high level winds carry this air towards the poles. The air gradually cools and eventually falls back to earth between 20 and 25 degrees south (exactly where the Atacama is), creating high pressure. Descending air warms up and any moisture in it evaporates into water vapour which is a gas and so doesn't bring rain.

And as if being in a rainshadow and having high pressure wasn't enough, the Atacama lies close to an ocean where a cold current flows northwards up the coastline. The Pacific Ocean is therefore colder than might be expected at this latitude. Any on-shore winds are chilled when they cross the current and don't have enough warmth to pick up moisture from the ocean surface. So, unlike most winds from the seas and oceans, these ones are dry.

There is no doubt that lack of water makes life a struggle for the people who live in the Atacama. However, the extreme dryness is not without its benefits. The Atacama desert is the only place in the world where saltpetre, a type of nitrate which used to be used in explosives and fertilisers, can be found. It's easily dissolved by rain so the Atacama desert is perfect for preserving it. Until the 1950s there were many small mining settlements in the Atacama like the ghost town of Humberstone which Mark cycled through. You can watch a bit of video footage of Mark in Humberstone.

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Another benefit is that the absence of clouds makes the Atacama the perfect place to watch the stars! When he was in the Atacama, Mark frequently commented on the clear night skies and said how much he was enjoying star gazing.

"The night sky in the Atacama is the best I have ever seen".
The clarity of the air has resulted in a number of observatories being constructed, the best known of which is the Paranal Observatory which Mark visited. You can which it houses.

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Here is Mark's photo of the Paranal Observatory and what he had to say about it...

"Sitting above 2500m, in a place where it never rains, many miles from the nearest light, makes this spot in the middle of the Atacama desert ideal for star gazing. Despite its remote location, this place must have the best road in Chile!"

I am writing this posting as news of Mark's successful attempt to summit Aconcagua is breaking. He has just climbed the highest mountain in the world outside Asia... but that is a Geoblog for another day.

Val Vannet

Would you expect to find penguins in the desert? Could there be ?

Clydeside Stories

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Claire O'Gallagher Claire O'Gallagher | 12:00 UK time, Tuesday, 26 January 2010

In case you missed it on ´óÏó´«Ã½2 - The LAB's Clydeside Stories was broadcast on Sunday, 24th January at 7.30pm. The project the result of a collaboration between the LAB and different community groups along the river Clyde:
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Pupils from Clydebank High School, members of Galgael in Govan and 71/2 John Wood Street Regeneration Centre in Port Glasgow all worked with ´óÏó´«Ã½ Scotland's L.A.B. team to make this programme. The groups brought together the stories, did the interviews and did the filming. Clydebank High School looked back at their old school and celebrated their new school building. 71/2 John Wood Street Regeneration Centre had an intergenerational group look at the regeneration of Inverclyde from different perspectives. Galgael, an inspirational project helping people with addiction problems get back into the working environment, found inspiration in rebuilding a sense of community.

Three different perspectives, three interesting stories, one changing river.

The programmes are available on iPlayer and on the LAB site.

The fifth capacity

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Claire O'Gallagher Claire O'Gallagher | 10:57 UK time, Monday, 25 January 2010

The introduction of has involved much discussion of the four capacities: successful learners, confident individuals, responsible citizens and effective contributors.

Some of the attributes of a 'responsible citizen' include having respect for others, with the ability to develop informed, ethical views of complex issues. The devastation in Haiti has led to many (largely unanswered) questions which could be picked up in classrooms around the world. How could we allow people to live in such dreadful poverty? Most pressing of all, of course: what can we do to help?

The has set up a campaign called '' which encourages schools to sign up and donate - there are also links and resources about teaching hunger issues available on their website. The is also looking for donations to help with the relief effort.

It seems to me that as teachers try to help the children in their care become rounded individuals, able to connect to each of the four capacities, that there is room for one more skill - to be a caring friend or neighbour. Some learners will draw upon their religious faith to do this; some, on their experiences within communities and families; some may ask the difficult questions mentioned above. All valid responses, which could be discussed and explored further in the classroom. This isn't always easy, as Kenny O'Donnell's honest and thought-provoking highlights.

The events in Haiti show us that there is scope to expand what we mean by a 'responsible citizen', by including the idea of caring. Respect is a great basis for citizenship, but I wonder if the' fifth capacity' has a place?

A History of the World

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Claire O'Gallagher Claire O'Gallagher | 15:10 UK time, Wednesday, 20 January 2010

A neat collaboration between the British Museum and different departments within the ´óÏó´«Ã½ has culminated in the launch of 'A History of The World in 100 Objects', a series for Radio Four. 100 objects have been selected from the British Museum which build a picture of local, national and international history through the ages.

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As well as the programmes, there is a lovely website showing off many more objects from across the UK's museum collections. Individuals and groups (I'm thinking classes?) will also be able to upload images that are of historical significance - whether it's a family heirloom or a statue in the local community, creating a 'digital museum' of objects.

There are already 60 artefacts, chosen by Scottish museums, that are available on ´óÏó´«Ã½ Local - why not have a look at your area's objects of interest?

Combined with the materials on the Scotland's History pages, I think these sites could make connections for learners between the local and international in ways they may not previously have thought of.

The historian Michael Fry has listed his in the Scotsman, using different criteria to the ´óÏó´«Ã½ site. I'm sure that our classrooms could also come up with fascinating objects for the digital museum.

You can also follow the History of the World blog, and there are lovely classroom resources on the website too for primary teachers to use - and if that's not enough there's a handy with everything you need to know about the project.

Surfing in the snow

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Claire O'Gallagher Claire O'Gallagher | 12:20 UK time, Wednesday, 13 January 2010

Happy New Year, one and all, and for those of you back in the classroom I hope 2010 has had a productive beginning.

School closures have been a permanent fixture of the news over the last week or so, with many councils unable to keep their schools open in the face of the weather. about his first experience of closing a school because of adverse weather got me thinking. A school closure is undoubtedly frustrating for teachers and parents (perhaps even for some pupils!) and is clearly , but it has made me think more about the role of online learning.

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An ideal situation in Scotland would have a system like able to transmit lessons via a webstream, so that learners can be taught even when they're snowed in. However, this isn't without its problems.

Firstly, the future of Glow is currently being debated fiercely (see the recent TESS piece on , and .) There's still a lot of about what teachers and learners want Glow to be able to do for them on a daily basis, never mind in a crisis situation where it could potentially enable learning to continue when schools are closed.

Even if that were established, this doesn't take account of the number of learners who do not have access to broadband internet at home. Glasgow, in particular, has been infamous for having the .

At times such as last week when so much of the country found itself unable to access basic amenities, digital accessibility becomes even more crucial. Schools and organisations such as ourselves must lead the way by encouraging young people to use the internet safely, rather than shying away from it.

I'm sure that if parents saw more of the educational potential of the internet, rather than being continually exposed to the negative aspects of the online world, many would be more likely to want an internet connection in the home.

It's the job of all of us to make sure that learning doesn't shut down when the schools do; and even when the schools are open, we all have to play our part in allowing learners to access the world beyond the school gate.

Image: by Lorne Robertson.

Update (18th January): Looks like some practitioners in Aberdeenshire were reading my mind - there is a lovely about using Glow in the snow. I notice their use of Learning Zone clips too!

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