Lightning has an electromagnetic personality

In the late 1700s, Charles Augustin Coulomb put the snap, crackle and pop from a number of perilous experiments together and deduced the form of the electrostatic force law. Here’s what he found:

  1. You can’t tell just by looking at an object whether or not it carries a charge. Unless you’re an X-Man. Possibly.
  2. There are only two types of charge: positive and negative. Opposites attract, as the old cliché goes. And an object with equal amounts of each is electrically neutral, like Switzerland.
  3. All normal matter contains electric charge (except Findus lasagnes, which are not yet understood by science).Electrons may be transferred from one object to another.
  4. In an isolated system, the total electric charge is always conserved. So when you rub a balloon on a cat, no charge is created – electrons are simply redistributed between the cat and the balloon (and anger is created in the cat. Cats are often not subject to the usual laws of physics. Mine can teleport). Charge has its very own law of conservation.
  5. Because of the attraction between unlike charges, any item with a deficit of electrons (which has, therefore, a positive charge) will attract negatively charged items. But that’s not all: it will also pull in any electrons that happen to be hanging around. That’s how electric currents work, in the very simplest terms. Put a negative thing next to a positive thing, and electrons will flow from one to the other until they’re sharing them equally.

Fun facts about electric charge

  1. A small plastic troll doll with purple hair. Looks like it's been introduced to a Van der Graaf generator.

    Me. On a Monday.

    If you super-dry your hair then give it a vigorous brushing, you can make it stand on end. I often don’t need to put this much effort in; my barnet’s natural state appears to be one resembling those little trolls. 

  2. You can stick balloons to the ceiling using electrons, thus defying the laws of gravity. This is an interesting demonstration of the difference in strength between the electrostatic force and the gravitational force. Relatively speaking, the electrostatic force is MUCH stronger. Mind-bogglingly so. (Although you can’t really compare them, because they are fundamentally different things with arbitrary units of measurement.
  3. If you’re wearing nylon clothes, and you take them off in a dark room, you can sometimes see sparks as the separation of the clothing from your skin causes the air around you to undergo electrical breakdown. You can dismantle the air, like an X-Man. Possibly.
  4. Electrostatic charges are responsible for lightning. (More below.)

One of my favourite things is finding out that an everyday (but brilliant) phenomenon is still not fully understood by our biggest brains. We really don’t understand how lightning works! Partly because experiments are bloody dangerous…

A scientist named Georg Wilhelm Richmann, a German physicist living in Russia, was killed during a lightning experiment in 1753. He has the dubious honour of being the first person killed during an experiment involving electricity.

He was electrocuted in St Petersburg while “trying to quantify the response of an insulated rod to a nearby storm”. Any excuse to duck out of a meeting, even back then: he dashed off on hearing the news of a thunderstorm, taking his engraver with him to record the event for posterity.

During the experiment, and somewhat predictably (with the benefit of hindsight), he was struck by lightning. (It’s said that it was ball lightning, a very rare phenomenon that wasn’t believed to exist until the 1960s.)

The explosion that followed blew up his shoes, singed his clothes and knocked him dead. That wasn’t the end of his scientific exploits, however; his body was dissected to find out what effect his terminal experiment had on his organs.

We don’t understand lightning

Lightning is probably the most dramatic and well-known natural phenomenon resulting from electrical charge. But how does it work? Well, here’s what we know:

  • On humid days, rising air currents carry water vapour up into the atmosphere.
  • This occurs in giant clouds – they’re around 10km thick.
  • The water droplets cool as they rise, then freeze to form hailstones. Hailstones are required for lightning to occur.
  • The hailstones grow as more water condenses on them, then begin to fall under gravity when they become obese.
  • As they fall, they tend to melt and emerge from the cloud as heavy rain.
  • Lightning flashes develop near the base of a cloud, and are caused by the separation of positive and negative charges within the cloud.
  • The electrical activity occurs at an altitude where the temperature is between 0°C and -10°C – the only temperature range in which both hailstones and supercooled water drops can exist simultaneously.

Beyond these facts, we’re not really sure of anything!

We all know what lightning looks like, but this video shows a whole plethora of beautiful phenomena set to the strains of Robert Miles epic tune ‘Children’. One of the soundtracks to my messy youth.

Theorising about lightning

Most of the theories about the origins of lightning are based on a transfer of charge between the rising water drops and the falling hailstones. This leaves the water drops with a net positive charge and the hailstones with a net negative charge.

With the water drops pulled to the top of the cloud by rising air currents, and the negatively charged hailstones falling under gravity, the result is a net excess positive charge near the top of the cloud and a net negative charge near the bottom.

The tops of clouds are happy. The bottoms are angry.

Diagram illustrating the charge distribution in a thundercloud.

This process increases until the electrostatic charges are so large that one of two things (may) happen:

  1. The vapour in the cloud undergoes electrical breakdown, allowing the electrons to flow up through the cloud in a giant spark of lightning – a ‘cloud flash’.
  2. The air beneath the cloud suffers electrical breakdown and the negative charge at the bottom flows to the positively charged ground as forked lightning.

As I said, though, the charging mechanism is not really understood. The middle of a thundercloud is a bit of a hairy place to be, so there are not many experiments documented. I quite fancy making some kind of protective bubble and mooching into a cloud. If anybody would like to fund this hare-brained scheme, do drop me a line. You could be in line to share a Nobel Prize, you never know…

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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?

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.

Unexpected Developments Scupper New Year’s Resolutions

On January 1, 2011, I wrote this post. So, as promised, I’m revisiting it. I was on a false high, and in complete denial about just how bloody miserable I was. I was also convinced that I would have achieved everything on my list. Well, that didn’t happen – but for once I’m not full of woe and self-recriminations.

This year has been a hell of a ride. I left The Worst Job in the World™ and, instead of wallowing, I slapped myself around a little then stood up. I held my head high, took a deep breath, set my shoulders back and my chin in the air, and Changed My Life.

With a little help from my friends, and a LOT of love, support and encouragement from my husband, my family and my splendid friends, I started my own business. Sunflower Communications was born in April 2012, and has been so successful so far that I can’t quite believe it.

Then, I became part-owner of Wylie’s, The Ironmongers with the fabulous Charlie Collett. Which was unexpected but brilliant. I’ve always wanted a shop. Next  year will be super busy…

2012 has been the hardest, in places worst, but generally best and most rewarding and satisfying year of my life. So I will forgive myself for not achieving everything on last year’s list:

  • Try something new at least once a week.
Me and my girls at our first burlesque show

My burlesque début!

Not quite once a week, but I have tried something new very often indeed. And each time, it’s enriched my life, even if I didn’t like it. Plus, this little resolution gave me burlesque, and a group of fan-bloody-tastic, strong, clever, funny, kind ladies who I love very much.

  • Buy more music.

This, I achieved. Florence and the Machine, Nina Simone, Imelda May, Propeller Heads, dubstep, Scroobius Pip…

  • Spend more time with my family.

This, too, I achieved. But it’s on this year’s list too.

  • Go to more gigs.

Although I did probably go to more gigs than I did in 2011, I would like to see more live music.

  • Improve my wardrobe: instead of purchasing several cheap items of clothing from random high street shops, spend a similar amount of money on one item that is beautiful, well-made, and will last.

I achieved this – and made my own clothes too! Long may this continue.

  • Motorcycle road trip around Europe with some good friends.

This was quite good fun 🙂

  • Become a bloody brilliant pole dancer.

Well, I don’t know about bloody brilliant, but I’ve certainly improved enormously. Which pleases me enormously.

  • Go clubbing several times.

I did this. It was okay.

  • Cultivate an aura of calm togetherness.

I don’t think that this is ever going to happen!

  • Embrace the fact that I am now a corporate whore.

I’m not! I’m not! I am a small business owner, and I am HAPPY.

  • Run at least one half-marathon.

Oops… This year though, for sure.

  • Be a better, kinder, funnier person.

I hope I have achieved this last one. I’ve worked hard.

Resolutions for 2013

This year, I am being a little more realistic. I’ve made a few resolutions over at my Sunflower blog, but they’re mostly business related. Here are my personal resolutions.

  1. Get away for a week with Joe. Just the two of us.
  2. Spend more time with our families, especially my lovely brother, his fabulous fiancée and my little niece Ella.
  3. Run more. I’ve joined Park Run, and I want to do a half-marathon next year, and perhaps a full marathon the year after. Perhaps.
  4. Read more books.
  5. Pay off the credit card.
  6. Spend more time camping and walking and bicycling and picnicking with good friends.
  7. More improvements in yoga and pole.
  8. Make more time for studying.
  9. Continue enjoying burlesque!
  10. Write more. Blog more. Rediscover my love for writing about science.

Happy new year

Happy new year readers. I wish you all the very best for 2013; and if life throws terrible things at you, I wish you the strength and courage to emerge from them stronger, with grace, and with your heads held high.

Big love. Peace out.