Saturday, 19 September 2015

When School-Children Asked Me How To Make A Bomb

As many students do, I spent a summer abroad doing a charity thing. Don't get me wrong, this was no posh-boy's year out, I raised pretty much all the money myself and it was via a university society which specialised in overseas aid projects.  But yes - it was one hell of a good time. I got to go to Nepal, which as a keen mountaineer at the time was a dream come true, if a little frustrating - I had a couple of thousand pounds to spend on my two months there, most of which was spent on flights, trains and directly to a school in Sundarijaal, just outside Kathmandu, and the lovely local family who housed and fed us.  Fancy actually going mountaineering in Nepal? Well you're going to need somewhere in the region of 100 times the money I had available for the project. I could see the classic summits from my books, but there's no way I was going to even set foot on them.

On the other hand, we lived and worked with some wonderful people, and helped lay the groundwork for a new school building, mostly by carrying saplings over the same two mile route up a hill and planting them to stabilise the land the school had been able to buy with, in part, the funds we raised from drunk people in Edinburgh.

But we also had a few days in the main school itself, which was incredible.  The kids were the best behaved and most intelligent you can imagine by UK standards. On my first day in the school the head teacher asked me what my area of interest was - science, and in particular physics, as you'll realise if you've read much of this blog.

So I was introduced to a class of around 30 kids, all around 14 years old (and bear in mind I'd just turned 18), and I expected to maybe help out as a bit of a classroom assistant.

"Hello class, this is Mr Robbins, he'll be teaching you science for the next hour."

Then she left.

"Mr Robbins?  Oh. Oh crap.  That's me."

So I'm left with my first, and to date, only classroom full of children who are looking at me and expecting something cool.

So fair enough, I realise, I'm kind of here as a novelty lesson, but at the same time I don't want to mess up any existing plans the teacher has.  So let's find out what they've been learning about so far.

As it turns out, a bit of everything - optics, basic electrical and electronic stuff, simple mechanics, everything you'd expect from a science class of the same age in the UK. Nothing, in particular, is a particularly important focus as far as the kids are concerned. Probably a good thing, because if they're really focussing on atoms and I start throwing quantum tunnelling into the mix just to be funky and interesting then they're all going to confuse the examiners at the end of the day.

"OK. So what do you want to learn about?"

One hand went straight up. "How do you make a bomb?" - the rest of the class seem to be in delighted agreement.

Which leaves me with a bit of a problem - because bombs are both deadly, and dead easy. There's an unspoken agreement between almost every geek on the planet that we don't generally talk about how to make bombs, because it's so damn easy to do. Especially in a country where you can buy reasonably large quantities of certain chemicals without suspicions being raised. UK, Nepal, wherever. Maybe a bit easier in Nepal in the 1990s than the UK today, but there's not an enormous difference.  And I quite like these kids, I don't particularly want to see any of them losing arms and legs, however much they enjoy my lesson.

On the other hand, there's one particular style of bomb that they can't easily make, but which has some lovely theory surrounding it. Atomic structure, chain reactions, a little bit of E=mc^2.

Yes, I spent the best part of an hour teaching kids how to make nuclear weapons.  And if anyone thinks that this is a fundamentally bad thing, I'll point out that at the time of writing a kid of the same age in the USA has been arrested for taking a home-made "breadboard" style electronic clock to school, on the grounds that it "looked a bit bombish".

Frankly, kids deserve better. I knew how to make a bomb, and had access to the materials, at around 14 too. Almost every kid of that age who can, doesn't.  Because being smart enough to build it means you're smart enough to not build it.  Arrest every kid who could and you end up with kids who aren't willing to admit they're smart, they just go and flip burgers for 20 years. And then they snap. And build their bomb.

Saturday, 7 March 2015

Scotland Calling

[The stats on this blog show the majority of my readers are in the USA, so for UK readers this post may seem to explain the obvious at times.]

We live in interesting times. The UK is a couple of months away from a general election, and we're looking at the most fractured and unpredictable split in voting for a very long time.

Since around 1930 British politics has consisted of two main parties, the right wing Conservatives (aka the Tories) and the left wing Labour party, plus lesser support for various incarnations of a middle-ground Liberal party.  We've always had other minor parties too, the far right British National Party, the Raving Loonies (a surprisingly long running "joke" party) and parties specific to the member nations - Plaid Cymru (PC) in Wales and the Scottish National Party (SNP) up here north of the border.  (Northern Irish politics is immensely complicated in its own right, I'm going to leave those issues aside for the moment.)

The last time the UK had a government that wasn't either Labour or Conservative led was in 1918, when the Liberals won. We're currently in the unusual position of having a coalition government of the Conservatives being supported by the much smaller Liberal Democrat party, but for the last hundred years or so the UK has basically been Conservatives versus Labour, and they've never seen eye to eye.

But Scottish politics has always been a bit different. We've consistently voted for left wing parties, traditionally Labour but with the SNP becoming more and more popular over the last thirty years. Since 1999 Scotland has had its own government which deals with purely Scottish matters (similar to the State v Federal split in the US), and despite being designed to prevent majority governments the SNP managed to win a majority of seats at the last Scottish election.  It should be pointed out that unlike most parties with "National" or "Nationalist" in their name, the SNP are on the left of the spectrum, generally described as social democrats - major policy splits from the main UK parties include providing free university education, a focus on renewable energy investment (Scotland currently produces over 40% of its energy needs from renewables, mainly wind and hydro), and crucially, a pro-independence stance.

As you probably heard, we held a referendum last year, asking "Should Scotland be an independent country?", which resulted in a roughly 55% to 45% vote in favour of staying within the UK, and saw an enormous turnout of over 84% of voters go to the polling booths, a figure unheard of in British politics.

During the hard-fought campaign most UK parties campaigned for a "No" vote (eg Scotland staying in the UK), and we saw the extraordinary sight of senior Conservative and Labour politicians stand shoulder to shoulder against the SNP (who were supported by minority Scottish parties including the Greens and Scottish Socialist Party).

This has caused a collapse in support for the Labour party north of the border. Now, while Scotland only return 59 MPs to Westminster (around 9% of the total), these seats are crucial to the Labour party. But now this support seems to be evaporating in favour of the SNP, who are predicted to win the majority of them at the next election.

All good for the Conservative party, you may think, but they've got their own woes in England, with the UK Independence Party threatening to take a lot of their support.

So we're in the odd situation of a predicted general election looking something like this:

Conservatives - 286 seats
Labour - 280
SNP - 38
Lib Dems - 24
Others (~6 parties) - 22
(Source -, figures at the time of writing)

In this situation no party has a majority, and under UK law the largest party must try and form a coalition. The SNP are opposed to Conservative policies to such an extent that they've already ruled out any kind of support, the Conservatives would have to gather the support of most of the Lib Dems and "others" to form a government.

If this option fails, Labour could form a government with the SNP, although the SNP have already ruled out a formal coalition, preferring to offer support on the basis of "confidence and supply" - if Labour propose policies the SNP support, they'll vote with them, but there's no guarantee.

Or, of course, there's the option of a Con/Lab coalition, something we've only seen before during wartime, and could cripple the support for the two main Westminster parties for years to come. This is generally seen as unlikely, but as we get closer to the election more and more people are putting it forward as an option.

So we've reached the weird point where the balance of power in the UK government could be held by a party who do not want to be part of the UK government.

So what's the SNP position on the continued fight for Scottish independence? It's not 100% clear. Their statement immediately after the referendum was that they would "continue to work for Scotland's interests as part of the UK", and it would clearly be a bit odd to hold referendum after referendum until they get the "right" result, it would make a bit of a mockery of the process.  At the same time, however, the close result last year and rise in SNP support has spooked the main parties to the point where they may never agree to another referendum anyway.

I suspect we'll see a gradual slide toward a federal UK, with Scottish, Welsh and Northern Irish parliaments gaining more powers and Westminster slowly being relegated to dealing with only UK-wide matters such as foreign policy and the military. This does leave the obvious gap of an English parliament, although the shout of "English votes for English matters" has become common ever since the referendum

After winning a vote to keep Scotland as part of the UK, the UK government now feel their greatest threat is Scotland - and the Scots, having voted to remain, find they have flipped the tables and have a new-found and far more powerful role at Westminster.

Who "won" the Scottish independence referendum? I'm really not sure, but the next five years are going to be interesting.

Thursday, 29 January 2015

Spontaneously Exploding Pint Glasses

Right, time to move away from the beer and back to the science - but I'm going to ease myself into it with a post on pub-based science.

This one has Glenmoray in it.

I have to admit to a whiff of paranoia when I
picked this glass up specifically for this post!

The classic British pint glass, the "nonic", is in my humble opinion one of the great pieces of design. It holds beer, you can stack them when empty (making a bartender's life so much easier), and the little bulge both improves grip and prevents the lips of two glasses from coming into contact, a little hygiene feature that nobody usually notices.

And they're tough, seriously tough. You can plunge a nonic into icewater straight from the glasswasher (at around 70C) and it'll cope with the thermal shock. You can stack them 30 high and they'll survive (not recommended for safety reasons, but you can).

The reason for this toughening is in the heat treatment they go through when they're manufactured. Each glass is slowly heated to around 720C and then rapidly cooled with chilled air. As the glass cools the inside (actually inside the glass, not "inside" as in where you put the beer) cools more slowly, leaving the whole structure under compression - it literally squeezes itself, resulting in a tougher glass that won't crack easily, and when toughened glass does break it does so in spectacular style, shattering into hundreds of small cubes and relatively few dangerous shards, meaning there's a much lower chance of serious injury due to accident or malice.

There is a downside to this heating process though, and it's all down to something called nickel sulphide (NiS).  This is a common contaminant in making glass and is very tricky to remove, especially when you're trying to make reasonably cheap glasses for pubs. It exists in two forms, or "phases", alpha-phase and beta-phase. The beta-phase is the everyday form, stable at normal temperatures, with the alpha-phase being stable at temperatures over 715C - crucially, this is just under the temperature required to harden the glass.

So when we rapidly cool our pint glass and it hardens we can end up with little bits of alpha-phase NiS stuck inside it, squeezed into not popping back into beta-phase because it would have to expand by about 3% to do so.

Now these "NiS inclusions" as they're technically called, will eventually pop back into the beta-phase, but it can take years. When they do though, they can cause an enormous amount of stress - up to 125,000 pounds per square inch, concentrated into a tiny area inside the glass. For comparison, the water pressure in the Mariana Trench, the deepest part of the oceans, is "only" 15,000psi.

This is easily enough to cause a crack to shoot through the glass at supersonic speeds, blowing the entire glass to pieces.

It's not a predictable effect, it can happen at any time. A slight shock to the glass (literally just flicking it with a fingertip in the right place) or even an ultraviolet ray from the Sun can set it off. Or it can just happen spontaneously, and there's plenty of reports of people's pint glasses simply exploding while sitting on a table. It's an interesting complaint to deal with as a bartender, in a decade behind bars I had to deal with incredulous customers twice and saw it happen to unattended glasses a couple of times.

The failure rate is small enough to be acceptable in pubs, especially given the other safety benefits of toughened glass, but this is a serious problem in glass being used for construction, such as modern skyscrapers and funky new bits of architecture, and is known as "glass cancer".

I believe this video is probably the result of a NiS inclusion - I'll buy a couple of pints for the first bartender to catch it on CCTV, statistics suggest it must happen weekly in the UK alone.

Further reading:
Nicely readable detail: Glass Breakage & Nickel Sulphide Inclusions  

NSFW but we're talking your-pint-exploding language: Real Life Account