Monthly Archives: January 2013

A short musing on snow

Twitter, Facebook and the bloke in the pub are waxing lyrical about how rubbish the UK is when it comes to snow. “It’s only a few flakes!” they cry. “Why does everything grind to a halt?” they complain. “Look at Canada – they cope with several feet of snow for weeks on end, and nothing stops!” they proclaim.

Well, yes. Of course they do. They have feet of snow every year, as do parts of northern Europe, North America and the Far East. They’re used to it. Their entire infrastructure is built around coping with large amounts of snow. Their populations know exactly how to prepare for the coming of snow, and how to perambulate and drive through it when it arrives. They all have snow shoes and snow chains, and it’s a way of life for them.

The UK, in contrast, hardly ever gets significant quantities of snow. Scotland and the higher areas of England and Wales do get more snow, and those areas cope pretty well. But they’re remote, and infrastructure is generally not affected. When populated, urban areas get blanketed, of course it causes disruption. We’re not set up to deal with it! Generally, we cope pretty well.

In 2010, we had lots of snow. I went up a hill, made snow angels, and danced. This is a photo of that.

Snow joke. It’s a snow dance.

By altering the way we do things slightly – like not travelling unless it’s absolutely necessary – the world doesn’t have to stop. In this age of technology, there is no reason why many office-based jobs can’t be done from home in poor weather, but this requires an attitude shift from senior management…

“But why don’t we set up our infrastructure to cope with heavy snow?” I can almost hear the wails from the legions of Daily Mail readers. The answer is simple: it would cost an enormous amount of money, and it wouldn’t be worth it. Not for our winters. Countries like Canada have built their economies and services around their climate; we haven’t. Unless our climate changes and we begin to have regular harsh winters like they do, it just isn’t worth it.

We’d do far better to alter our working practices where we can, and adjust our driving to the weather conditions (something surprisingly few people do). But having a good old moan about how rubbish Britain is, is one of our national pastimes, so I guess that will carry on. People really should stop panic buying everything though. It’s probably not going to be that bad in most places. And I need to do my normal shop tomorrow…

Anyway: stuff this. I’m going out to build a snowman. Did I mention that I LOVE snow?

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Our Slow-Burning Star

IMG_0814Ever wondered why the Sun hasn’t burned out yet? Or why, exactly, it will still be going in several million years?

‘Well, it’s very big!’ I hear you say. ‘There’s lots of fuel in there.’ Yes; yes, it is very big, and there is a lot of fuel. But that’s not why it’s such a long-term heat and light source. It is a little more complicated than that…

Here’s an interesting fact: kilogram for kilogram, the Sun puts out less energy than a human body. It is far less efficient than we are at generating power.

On the face of it, this is a little surprising – it’s an enormous flaming ball of gas that we couldn’t get anywhere near without disappearing in a puff of carbon. So how can it be so inefficient?

The answer lies in the fact that it is, indeed, a great big ball of gas and it behaves in a very similar way to gases on Earth. It turns out that gases are rather interesting and the way they behave under different conditions is predictable.

The Maxwell-Boltzmann curve

The distributions of speed and translational (movement) energy of the molecules in a gas are very similar if a gas is in equilibrium. The more molecules the gas contains, the fewer fluctuations in speed and energy distribution.

Essentially, this means that a certain percentage of gas molecules will tend to have a certain speed or energy level. This is best demonstrated using a Maxwell-Boltzmann graph:

A graph showing the Maxwell-Boltzmann curve of molecular speed distribution, with the most probably speed indicated.

The Maxwell-Boltzmann curve of molecular speed distribution

This graph shows that there is a most-likely speed for any given gas molecule to have (and a similar curve exists for molecular translational energy). As long as the temperature of the gas is constant, the fraction of molecules with the most probable speed remains around the same (as does the fraction of molecules with any other speed).

(Note that molecules with a given speed may not be the same; their individual speeds keep changing as a result of collisions with other molecules, or the gas container.)

The graph has a long tail at higher speeds and energies: the likelihood of finding a molecule with a certain speed and energy decreases as speeds and energy levels increase. It’s the same for protons in the Sun.

This is the reason for the Sun’s longevity: the chance of two protons coming together in nuclear fusion is tiny. It has been estimated that it takes one proton five billion years to fuse with another proton. Most of the time, protons zip around in the Sun at relatively low speeds and energies, bouncing off one another and carrying on their merry way.

They are to be found in the ‘lumpy’ part of the distribution curve; the area with the ‘most likely’ speeds and energies. It is only when a proton (or molecule) falls into the tail end of the curve that it approaches the speed and energy required to undergo fusion.

A graph showing the energy distribution curve of protons in the Sun, with the area where fusion will occur highlighted in purple.

The tail-end of the energy curve, where fusion will happen.

Most of the Sun is too cold for fusion. When those very few protons in the tail end of the distribution curve do come together in fusion, they release large amounts of stored energy.

It is, therefore, extremely unlikely that fusion will occur in the Sun. However, it’s so massive that its total energy output is enormous so it is pretty hot. And bright. If the distribution patterns of speed and energy were different, the Sun could have burned out millennia ago, or may never have got very hot at all.

Gases are predictable

The speed distribution of a gas depends on the mass of the molecule, but the translational energy distribution is the same for all gases at the same temperature.

In other words, the larger the molecules’ mass, the slower their speed; so the speed distribution will be affected by molecule size. However, the molecules’ mass has no effect on the energy distribution – it’s the same for all gases at a fixed temperature.

  • The speed and energy of a gas’s molecules increase as the temperature increases, as long as the volume is fixed.
  • The molecules’ energy is unaffected by a change in speed at a fixed temperature and volume.
  • The speed and energy are unaffected by an increase in volume, at a fixed temperature.

These properties have been extremely useful in the development of technology – and led to the invention of a simple but quite marvellous fire-starting device: the fire piston.

Because compressing gases leads to an increase in temperature, if you do it quickly enough you can ignite flammable material without any need for sparks or traditional fuel. An old-fashioned fire piston is still useful today for campers, climbers and other such adventurers. It’s small and easy to use: take a long, thin cylinder, a rod or piston, and place some flammable material in the bottom of the cylinder. Plunge the piston down rapidly, and watch the material ignite. This video shows you how to make one, which I will do at some point:

Science in action. It’s marvellous!

For My Grandad

Ambrose Charles Quinn, known to one and all as Charles, was born in 1916. He was tall and kind and funny and clever and strong and always there, with tales to tell of hijinks on motorcycles, beautiful cars, days of yore and warm family holidays filled with love.

He was my Grandad, and he died this afternoon. I miss him already.

Jean Quinn and Charles Quinn, my lovely nana and grandad, dressed up at my wedding in 2009

My Nana and Grandad.

Some of my earliest and fondest memories are of school holidays spent with Nana and Grandad and Tosca, their gorgeous dog. We’d go walking, or tinker with Grandad’s latest car, and the house would smell of rich stew, our lunch.

In the cupboard – behind the sliding doors of the sideboard – was a stash of Grandad’s Mints. I’ve no idea what they’re really called; they are white, and roundish, and crumbly. Grandad’s Mints. They were always there and there was always one for me and Richard. And the dog.

It’s the little things you remember; the dog walks in the bluebell woods, the Pembrokeshire coastal path, sand castles on Marloes Beach, and slideshows. Grandad’s way of telling a story, dotted with ‘buggers’ and ‘bloodys’ and earning a raised eyebrow or a tut from Nana.

He had a Panther ‘thumper’ motorcycle; way before I was born. He put a sidecar on it. With Nana on the back, and my dad and his sisters in the sidecar, they went off for daytrips and holidays… He loved his caravan too. I don’t think there are many places in Britain that Nana and Grandad didn’t visit. He loved England, our countryside and coasts. Too much to see, and not enough time.

When he couldn’t drive any more, he took a great interest in everyone else’s cars. And he was delighted when I learned to ride a motorcycle! He knew engines inside out, and rebuilt, renovated and fixed up a dazzling series of cars. The one that sticks in my mind is a white Jaguar, from the days when cars were truly things of beauty and they all looked different. Grandad loved cars and motorcycles, and he passed that enthusiasm onto my dad, and onto me. Thank you.

Then I met and married my Joe, and Grandad loved him. They’d talk for hours about bikes, and bike trips, and travels and broken vehicles.

He married my Nana 70 years ago. Seventy years! Platinum, apparently… You can’t find a card. We had a party, which was lovely. They were married for 70 years, happily, and wonderfully.

How to fit 96 years into a blog post? And do justice to someone so lovely? Clearly I can’t. And now I can’t believe he’s gone. He and Nana, and my Grandma, have always been there.

Sleep well and peacefully Grandad. Thank you for everything. I love you.

Why I love science

Or, at least, this is one of the reasons I love science…

Take a look at this article in Nature. It’s interesting, yes – especially if you understand anything of quantum gases. But it’s the comments that made me laugh!

The article also underlines our everyday misunderstanding of and misuse of terms such as ‘temperature’ and ‘heat’.

Dive in!

Nature article

Science also invites respectful, light-hearted banter. Compare this to the trolling and abuse you often see in the comments sections of blogs and YouTube…

2012 in review

It’s always interesting to see how you’re doing in the blogosphere. Surprisingly well! And my new year’s resolution to blog more should help…

The WordPress.com stats helper monkeys prepared a 2012 annual report for this blog.

Here’s an excerpt:

4,329 films were submitted to the 2012 Cannes Film Festival. This blog had 27,000 views in 2012. If each view were a film, this blog would power 6 Film Festivals

Click here to see the complete report.