Category Archives: Random

Monstrous Moles: Happy Mole Day!

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Happy Mole Day! It’s the 23rd of October and, at least where I am right now, it’s still between 6:02 am and 6:02 pm, so that means it’s time for chemists to celebrate! Of course, I’m in the U.K., so the date thing doesn’t quite work — for me this is 23/10, not 10/23 — but since there are only 12 months in a year (even in 2020) the British system is a bit unsatisfactory, so I’ll go with the American date format for the day.

There are literally loads of atoms in everything

What’s a mole? Well, to paraphrase Douglas Adams: atoms are small. You just won’t believe how vastly, hugely, mind-bogglingly small they are. I mean, you may think the latest incarnation of the walnut whip is small, but that’s just peanuts to atoms. Or even walnuts.

There are literally loads and loads of atoms in everything. There are so many of the blasted things that the numbers are a real pain to deal with. A teaspoon of table sugar, for example, has about 7,400,000,000,000,000,000,000 sucrose molecules in it, and since each sucrose molecule contains 45 atoms, that’s a whopping 330,000,000,000,000,000,000,000 atoms. And that’s not even a heaped teaspoon.

Even if we used standard form and wrote that last number as, for example, 3.3 x 1023 it’s a bit of a pain. And chemists are far too busy to write things out in full — why do you think they came up with all these symbols in the first place? — so what we do is we pick a convenient amount, which turns out to be 6.022 x 1023, and call that a “mole”. It’s just like calling twelve eggs “a dozen” only, you know, bigger.

I’m not going to explain the origin of the actual number further than this. There’s an awesome graphic here from Compound Interest and, if you want to know more, just click through.

What I am going to do are some… interesting mole calculations. People usually do grains of sand or coins or something. But those are so boooorrring. It’s nearly Halloween, right? I say we go gruesome.

Let’s start with blood!

A healthy adult has about 35 trillion red blood cells in their body at any given moment. (Vampires, presumably, have even more… although… do vampires make their own blood supply? Interesting question…).

35 trillion is a big number, right? A trillion is a million million (on the short scale, which everyone uses, don’t start), 1,000,000,000,000, or 1012, so 35 trillion is 3.5 x 1013.

But that’s only 0.000000000058 of a mole! Even if we count everyone on the planet, we only get to 0.45 of a mole. Yes, that’s right. Even if we drained the blood out of every, single human on the planet, we’d only about half a mole of red blood cells.

Ooh, how about bacteria? We have a lot of those on us, right? In fact, we have more microbes in and on our bodies than human cells! (Well, we can argue about the definition of “human” here, I suppose, but… let’s not.) Apparently there are around 3.8 x 1013 bacteria in our colons which means… damn. This is the blood cells thing all over again, isn’t it? If we took all the humans on the planet, sucked out their gut bacteria (don’t ask) and collected it all together (really, don’t) we’d have, yes, a little under half a mole of microbes.

Don’t tell the tooth fairy’s boss. She really IS scary.

Okay, this is all very well, but it’s not helping us get an idea of scale, is it? All right. Let’s try human teeth. Why not? I mugged the tooth fairy for this one (she’s much tougher than she looks), and it’s about 8 mm long. Adult teeth are a bit larger, of course, but the fairy has less of those. Let’s assume 1 cm to make things easier. That’s 0.01 m. If we had a mole of human teeth they would stack up to… 6.02 x 1021 metres, or 6.02 x 1018 km, or (we need to ramp this up a bit) about 640,000 light years. That would reach a little dwarf galaxy in the constellation of Canes Venatici, somewhere in the general neighbourhood of the Milky Way. Or, alternatively, to Neptune and back…. some 670 million times. Gosh.

What about… hair? A fine human hair is about 0.05 mm across, which means a mole of (fine) hair would be 3.01 x 1019 metres thick. The diameter of the Earth is 12,700,000 metres so that’s about… 2,400,000,000,000 times wider than the Earth. Even Rapunzel might struggle with that much hair.

There are about half a mole of red blood cells in all the humans on the planet.

Hang on, let’s go back to those red blood cells for a minute… okay, if there’s about half a mole of red blood cells in all the humans on the planet, and we assume a single red blood cell is 7.8 μm (0.0000078 m) if we put all those red blood cells in a line it would be…2.3 x 1015 kilometres long. The circumference of the sun is about 4,400,000 kilometres so…

… with all the people on the planet, we could make half a billion rings of blood around the sun, one cell thick.

There’s a thought.

In summary, the mole is a flipping big number. Too big, really, to count anything other than atoms (or molecules, or ions). But it is useful for that.

Happy Mole Day!

Look, these numbers are big, right. I’m going to be amazed if there isn’t some sort of order of magnitude mistake. Just… let me know.

If you’re studying chemistry, have you got your Pocket Chemist yet? Why not grab one? It’s a hugely useful tool, and by buying one you’ll be supporting this site – it’s win-win!

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Want something non-sciency to distract you from, well, everything? Why not check out my fiction blog: the fiction phial.

The UK’s Unlikely System of Units

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The novel Good Omens was first published in 1990. And this is my original copy.

Unless you’ve been asleep for the last few months (if so, are you a snake, by any chance….?) you will have noticed that there’s recently been a very popular television adaptation of the much-loved book by Terry Pratchett and Neil Gaiman: Good Omens.

I have always loved this book, and I love the TV show even more. Obsessed? Erm. Anyway. Can I wring a science-themed post for my blog out of a story about a demon and an angel saving the world from Armageddon? Of course I can.

Here goes. There’s a moment in the second episode of the TV adaptation* when the demon, Crowley, is driving his Bentley very, very fast, and the angel, Aziriphale, says: “You can’t do ninety miles an hour in central London!”

This caused a bit of confusion for some non-British viewers§. Not the idea that you can’t, or at least shouldn’t, drive extremely fast in a built-up area, but rather the fact that Britain is a European country, isn’t it? At least, for the moment. Don’t the Europeans use the metric system? Shouldn’t he have said one hundred and forty-five kilometres per hour?

So you thought Brits used the metric system? Haha.

I mean, okay, we do. Scientists in particular are quite keen on it. But we also use imperial units really quite a lot. And coincidently, this all arose just after the politician Jacob Rees-Mogg issued a style guide to his staff declaring that they must “use imperial measurements” — which at first sounds typically Victorian of Rees-Mogg, but actually… if your aim is to at least try to be consistent, he might, just might, have a point…

Allow me to try to explain.

Firstly, a little clarification: the “metric system” is an internationally-recognised decimalised system of measurement, that is, a system where units are related by powers of ten. I stress this because “metric” and “decimal” do not mean quite the same thing, which is relevant when it comes to money. The metric system takes base measurements — kilograms, metres and so on — and says that all versions of those measurements can only be connected by powers of ten, and must not introduce new conversion factors. So, grams (1000th of a kilogram) and tonnes (1000 kilograms) are both metric, but a pound (0.454 of a kilogram) is not. Scientists know this as the SI system of measurements. Okay? Right. Let’s get on to the amusing cocktail of units the British have to cope with in their every day lives…

Britain loves inches.

Length
The length of small-ish objects is measured in centimetres and millimetres. Sometimes. Except the diameter of pizzas, the sides of photos and photo frames, and the diagonal of laptop screens and televisions — all of which are almost always given in inches. Screws, as in woodscrews, are often given in  fractions of inches. Let’s not get into jewellery, for that way madness lies.

Longer objects are measured in metres and centimetres, except for the height of people, which is almost always quoted in feet and inches. Chippies (that is carpenters, not people that cook fish and chips — keep up) tend to colloquially use feet and inches for planks of wood. For example, “I need a bit of six by nine” — meaning a piece of wood 6 feet long and 9 inches thick.

What do you mean, how do you know which one is 6 and which one is 9? You’d hardly have a 9 ft piece of wood that was only 6 inches thick, would you?☨

People do sometimes use metres for short walking distances, e.g. “it’s fifty metres to the shops”, however Brits also like to use yards, a yard being 3 feet. But that’s okay, because a yard is close enough to a metre as to make little difference to a casual walking estimate, so they’re pretty interchangeable.

Marathons are measured in miles. Shorter road races use kilometres.

The sorts of distances involved in lengthy travel are always measured in miles. The distance from Oxford the city to Oxford Street in London, for example, is about 55 miles. No British person would ever describe this as 88.5 km. Speed, as we saw in Good Omens, is thusly described in miles per hour (mph). For the record, the speed limit in a built-up area such as Oxford Street would normally be 30 mph, or sometimes (more and more frequently) 20 mph. Crowley was indeed driving ridiculously fast, but then, he has demonic magic to help him avoid both pedestrians and police.

Miles are also used for marathons. However, not for shorter running races, which are often described as “5k” or “10k” meaning, obviously, 5 kilometres or 10 kilometres. The cynics may wonder whether this is because 5 kilometres sounds longer than 3 miles, but I’m sure runners aren’t concerned about such vanities.

Is all of that clear? Okay, let’s move on…

Weight
Weight (physicists: I mean mass, yes, you’re very clever, shhh now) of people is measured in stones and pounds (there are 14 pounds in a stone). Except for babies, which are little and are therefore measured in pounds, because everyone knows a baby ought to weigh somewhere in the region of 7 pounds or so, and if you quote a baby weight in kg, Brits have no idea whether to gasp, coo, or wince sympathetically.

The weight of food is mostly measured in kilograms and grams (or possibly grammes; it’s essentially the same thing) these days, although a lot of people still favour pounds and ounces. This leads to oddities, such cake recipes which call for 225 g of butter (half a pound). There are, by the way, 16 ounces in a pound, because it would be far too easy if it were consistent with the pounds/stones thing, wouldn’t it. Oh, and Brits have quarter pounder beefburgers in restaurants — none of that ‘Royale with cheese‘ business for us, thanks.

Larger weights are mostly quoted in tonnes, because that’s easy, but sometimes we use tons as well, which has the added amusement of sounding exactly the same when you say it out loud. 1 tonne is about 1.1 tons, so it’s not too much of a problem unless you’re planning a really big building project. Very large amounts are sometimes given in hundredweight, which sounds metric, doesn’t it? It’s not. A hundredweight is 50.8 kg, or 112 pounds. Did you think it would be 100? Yes, well, there are reasons.

Once again, let’s not get into jewellery. If we start on carats we’ll be here all day.

Beer, blood and milk are measured in pints.

Volume
Small volumes of liquids tend to be measured in millilitres or (particularly for wine) centilitres. The exceptions are beer, blood and milk — which are given in pints. Wandering into a British pub and asking for half a litre of beer is guaranteed to cause everyone to stop what they’re doing and stare at you. As will asking for pint of blood, for different reasons.

Larger volumes are measured in litres. We’ve mostly given up on gallons, now that all the fuel stations quote their prices in pence per litre because it looks cheaper that way.

Chemists like to be awkward, though, and use cubic centimetres — written cm3 or occasionally cc just for fun — for small volumes of liquids, and dm3 (cubic decimetres) for litres. 1 cm3 is 1 ml and 1 dm3 is 1 litre, so there’s really no reason for any of this other than to confuse students.

Temperature
Temperatures are mostly quoted in Celsius (aka centigrade, well, more-or-less), and most Brits these days have a fairly good feel for that scale. But Fahrenheit still gets rolled out when either a person or the air gets hot. A midsummer’s day might reach ‘100 degrees’ (that is, a little under 38 oC) and someone with a fever might also be described as ‘having a temperature of over a hundred’. Once it gets chillier, however, we’re firmly back to Celsius, because ‘minus five’ sounds a lot more dramatic than 23 oF.

In case you’re wondering, no, I did not choose this particular picture of a thermometer by accident.

In case you thought you were on safe ground here, don’t forget there’s also Kelvin (where 0 oC = 273 K) which is the SI unit of temperature and very popular with physicists. And, if you’re cooking, the mysterious ‘gas mark‘ — which is more-or-less unique the U.K. and which is based on some sort of occult formula. (Gas mark 6 is about 200 oC or 400 38 oF.)

Energy
Energy is measured in Joules. Except when it comes to food, where it’s measured in calories. Actually, kilocalories, but everyone just calls them calories. There’s meant to be a capital C to help tell the difference, but no one ever remembers. This is all fine.

Pressure
Are you sure you want to go here? Okay. FINE.

Tyre pressures are quoted in pounds per square inch, that is, PSI. Most British car owners can probably tell you roughly what their tyre pressures ought to be in PSI, even if (having learned metric at school) they have a somewhat shaky grasp of what either inches or pounds are.

Atmospheric pressures are usually quoted in atmospheres, because everyone knows what that means (sea level is one atmosphere, give or take). Of course, that’s not the SI unit, which is Pascals: 1 atmosphere is 101,325 Pascals, which is a bit unwieldy, so scientists often use bars, where 1 bar is 100,000 Pascals, and thus 1 atmosphere is more-or-less 1 bar, which, for once, is sort of helpful (no, really).

Blood pressure is usually quoted in mmHg

But then there’s also Torr, which arises from the historical practice of using mercury to measure pressure. 760 Torr is 1 atmosphere, while 1 Torr is 133.32 Pascals. Blood pressure, of course, was traditionally measured with a mercury sphygmomanometer, but just in case you thought you were on top of this, 1 Torr is nearly, but not quite, the same as the measurement in that case, which is mmHg, 1 of which is equal to 1.000000142466321 Torr.

Money
British money is decimal (but not metric, for the reasons described back at the start there), but only became so in 1971. If Rees-Mogg has his way I’m sure we’ll be back to pounds, shilling and pence before we know it.

It’s all your fault, isn’t it, Crowley?

In summary….
Since no one in this country is going to give up miles any time soon, if you want to be consistent about units it makes a certain kind of sense to insist on sticking to imperial, I suppose. As much sense as imperial measurements make anyway, which is not much.

You do have to wonder how we ended up with such a confusing mixture of measurements. It’s almost… demonic….

* Page 51 of the original print edition, second line up from the bottom. Obsessed? No idea what you mean.
§ And possibly non-British readers of the book in the 1990s, but Twitter didn’t exist then, so any puzlement went largely unnoticed. It was a quieter time.
☨ would# you? I don’t bloody know. Apparently it’s obvious.
# or, indeed, wood.

Escape Artists Podcasts are brilliant and you should download and listen.

Would you like to listen to the lovely Alasdair Stuart and me natter on about how utterly brilliant Good Omens is, and all the clever little things we spotted in the show for about an hour or so? Of course you would! It’s part of the premium content bucket at the EA Podcasts Patreon. Please do consider supporting Escape Artists podcasts; they produce truly brilliant fiction podcasts on a weekly basis. If you’ve never heard of them (where have you been?) why not subscribe to their free podcasts: Podcastle (fantasy), Pseudopod (horror), Escape Pod (science fiction) and Cast of Wonders (young adult).

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Chemistry jokes get the best reactions

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Today, 24th March, is Red Nose Day 2017 in the UK. I decided to see if I could collect some new chemistry jokes. There are some, of course, that we’ve all heard before – we might even say that all the best ones argon.

So, I promised to donate £10 if I got sent at least five new jokes. And I did! So I have! And here are my favourite five, in no particular order. Enjoy!

“I’ll tell you a joke about a tiny amount of iron for a small Fe.” — @hullodave

“Chemistry Fact: There’s really no such thing as hydrogen. The inventor of the Periodic Table just needed a place to land a tiny helicopter.” — @hullodave

“Why don’t they galvanise ships to stop corrosion? …That would make them zinc.” —

“Do you know why everyone wants to work with bismuth? Because there’s no bismuth like showbismuth!” — @GriceChemistry

“I know a great long Justus Von Liebig joke but it needs condensing to get it on Twitter.” — 

If you’ve enjoyed these, if they’ve even so much as made you crack a little smile, please go and donate a couple of quid to Comic Relief. It’s a brilliant charity which helps people all over the world.

Donate here

Five science facts we learned at school?

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This week a post called ‘Five Science ‘Facts’ We Learnt At School That Are Plain Wrong‘ popped into my Facebook feed from a few different sources.

It led to more than one argument, and the unearthing of some interesting titbits. Most of these facts aren’t directly about chemistry, but hey, still interesting. Let’s have a look:

We’re taught we only have five senses: smell, sight, hearing, touch and taste
True enough that there are more than five, but I clearly remember being told in school that balance and pain were also senses, so I’m fairly sure biology teachers have been quietly trying to dispel this one for decades.

plastic paperclips

Non-magnetic paper-clips. Ha!

Which of the following are magnetic: a tomato, you, paper-clips? (Answer: all of the above)
I think this is a misleading question. What do you mean when you say ‘magnetic’? I think most people understand that to mean something that’s capable of being magnetised or at least is attracted to your everyday fridge magnet. In other words, the ferromagnetic materials: iron, nickel, cobalt and most of their alloys. True enough tomatoes and people interact with magnetic fields (this is the basis behind MRI scanners – check out these beautiful images) but does that make them magnetic? We-ell….technically…. (there are lots of types of magnetism) but it seems a bit mean to criticise an assumption by asking a less-than-clear question about it. Besides, if you’re going to be pedantic about it, what’s that paper-clip made of hmm? Plastic and aluminium (both generally considered to be completely non-magnetic) paper-clips exist. Bad question. Next!

CMYKThe true primary colours for paints and pigments are cyan, magenta and yellow
Broadly fair enough, look at your printer cartridge. Although we really ought to include black as well (which the original article didn’t mention; it’s the K in the CMYK model). You can make something pretty close to black by mixing the others, but it’s not the nice, crisp, blackest black that people want for text and outlines. All that said, to actually get red from a mixture of magenta and yellow you have to have pretty pure pigments. Grab a paint box and try mixing something that looks like magenta with something that looks like yellow, and you’ll actually get something that looks like orangey-pink (serious artists agree that if you want really bright red, you’re better off just buying some red pigment). Whereas if you mix blue paint with yellow paint you will, fairly reliably, get green of one shade or another. I just worry that attempting to clear this one up is going to cause a lot of children to mess up their paintings. That’s all I’m saying.

A little addition here: this question then led to a debate about the colour spectrum of visible light. How many colours are there, exactly? It’s commonly held that Newton invented the colour indigo because he felt, possibly for superstitious reasons, that there ought to be seven colours. As a result, some people will tell you the spectrum actually consists of six colours rather than seven: red, orange, yellow, green, blue and violet. But hang on. Look at a spectrum (here’s one):

600px-Spectrum

What’s that colour in between blue and green there? You might say turquoise, but in a return to the original question it’s more accurately named cyan. That band is pretty obvious. I’d argue that if you’re going to include orange in the spectrum, then you ought to include cyan. And, in fact, some people think that’s exactly what Newton was doing. Except he didn’t call it cyan, he simply called it blue. The bit we think of as blue is what he named indigo. In other words, the spectrum is, in fact: red, orange, yellow, green, cyan, blue, violet. Still seven colours, they just don’t quite fit with the whole Richard Of York Gave Battle In Vain thing.

Of course, those of us in the know are aware that there are actually eight colours. But you need to have octagonal cells in your eyes to see the other one. Or be a cat.

pzg3m9pk-1414136926

Debunked in 1974. Still hanging around like a bad smell or, er, taste.

Tongue taste maps are nonsense
Yep. This one is unambiguous: there aren’t regions for sweet, salt, bitter etc. on your tongue. This was debunked back in 1974, but it’s still hanging around for some reason.

There are more states of matter than just solid, liquid and gas
Ah-ha, a chemistry one! Again, this is true. The strict states of solid, liquid and gas are fine when you’re talking about elements and pure, fairly simple, compounds (water, for example), but matter can indeed take other forms. There are ‘liquid crystals‘ – you’re probably reading this right now using some – and yes, there’s plasma. Once you get into mixtures all bets are off (no, you can’t melt wood, sorry). And colloids are a whole other kettle of fish.

But I think this is one of those times where you have to ask yourself why are we bothering to talk about solids, liquids and gases in the first place? Is it purely so that students can memorise three words? No. It’s so that they can go on to understand the concepts of melting and boiling, and their partners freezing and condensing. These ideas are critical to understanding ideas of measuring temperature as solid liquid gaswell as what happens to particles when they warm up (or cool down). Adding other technical terms in at this early stage is just likely to cause confusion. I don’t think that learning about the transition from solid to liquid to gas precludes later learning about liquid crystals, colloids and the like (hey, it’s how I did it). You’re just adding more information to a simple model, and someone studying A-level sciences and beyond ought to be capable of dealing with that. No harm, no foul, I say.

So there we have it: less “Five Science ‘Facts’ We Learnt At School That Are Plain Wrong”, and more one thing your teacher probably tried to correct you on, one misleading question, one thing you might have learned incorrectly at school, and a couple that might be technically untrue but it doesn’t really matter that much in the long run. But I suppose that IS less of a snappy title for an article.

Truth, Justice, Freedom, Reasonably Priced Love, and a Hard-Boiled Egg.

Creepy combustion chemistry…

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Halloween pumpkins

We’re burning!

So it’s October and I’m trying to think of a blog post topic. Hmm.

Well, the Nobel prize for Chemistry was announced earlier this month. But it went to some guys who’d developed a microscopy technique for seeing single molecules, specifically molecules involved in cell interactions. All very nice, but that’s biophysics isn’t it? Why did it get the Chemistry Nobel? (Biology famously doesn’t have it’s own Nobel prize, so maybe the committee just had to sneak it in somewhere?)

What else happens in October? Halloween of course! I love Halloween. But I’ve done pumpkins before. And I’ve written about sugar and chocolate, so that’s tick or treating more or less covered… hmmmm… candles, vampires, ghosts, the paranormal…

250px-Human_Torch

Is anyone else hot? (The Human Torch, art by Adi Granov)

Ahah! Inspiration! Spontaneous human combustion. What else?

If there’s any paranormal topic that touches on the edges of chemistry, it has to be this one. If you’ve never heard of it, spontaneous human combustion refers to the idea that humans can (or, er, maybe not – bear with me) suddenly and unexpectedly burst into flame and be reduced to ashes in a matter of moments. There is apparently no external source of this flame – it seems to come from nowhere.

It’s a creepy idea. I remember one of my chemistry professors at university, who had turned up to lecture us in his chemical-stained lab coat, with bushy white hair and too-dark eyebrows sticking out in all directions, pausing on his way out to tell us that we should think carefully when deciding whether chemical reactions would happen spontaneously or not under real world conditions. “After all,” he said cheerfully, “spontaneous human combustion has a negative Gibbs free energy, and you haven’t all burst into flame. Yet.”† And with that he gave us all an ever-so-slightly crazed grin and sauntered out of the room, leaving us looking around uneasily for traces of smoke.

Gibbs free energy change is a measure of how energy changes during a chemical reaction. It’s linked to couple of very important physical laws that pretty much describe how the world works. In short, do a bit of maths and, if you get a negative number, it tells you whether a chemical reaction can occur spontaneously but, and this was my lecturer’s point, not necessarily whether they actually will. It’s a subtle distinction, and one that’s easily forgotten. (Crucially, activation energy needs to be considered as well – if you want to know more about these terms, follow the links.)

Theatrically-minded chemistry lecturers aside for a moment, the idea that people, and things, might unexpectedly start burning is an old one. You can track it right back to the Old Testament, where there was quite a lot of suddenly bursting into flames going on, for example the angel of the Lord appearing to Moses in flames of fire from within a bush. Mind you, that was an angel rather than a human being, and they might be flame retardant of course. But you get the point. Fire has always been important to humans as a source of vital light and heat – indeed many would argue that the ability to control fire was a key turning point in human evolution – but at the same time it can be horrifyingly destructive. It’s hardly surprising that fire has found its way into so much of our history and mythology.

Let’s think about what the combustion part of ‘spontaneous human combustion’ means. The definition of combustion is a chemical reaction between a fuel and an oxidant (commonly oxygen) that gives out heat.

270px-STDevil_inTheDark

This applies to you, unless you’re a silicon-based lifeform.

There is more than one type of fuel, but the most familiar ones (coal, oil, gas, fats, wood and so on) are made of largely of carbon, hydrogen and oxygen. You are made up of the same elements (assuming you’re not some kind of alien life-form who’s stumbled over my blog – in which case, welcome). Of course you do have some other elements thrown in as well, notably nitrogen, calcium and phosphorous, but most of you is carbon, oxygen and hydrogen.

When you burn these kinds of fuels, this happens:

fuel + oxygen –> carbon dioxide + water (+ lots of energy)

Fuels give out lots of energy when they burn, and so, in theory, would you. Particularly if you have plenty of fat, because fats burn really nicely. After all, what were candles made of before paraffin wax? Largely tallow – which is a processed form of animal fat, usually from cows or sheep. And we all know that candles burn really well, that’s sort of the point.

The idea that you can burn a human isn’t surprising, after all people have been using fire to dispose of human remains for thousands of years. But spontaneous human combustion (SHC) is something different. In these cases, the person burns without any (obvious) source of ignition. At this point, you might be imagining a person suddenly bursting into flame right in front of shocked witnesses, but in truth reliable eyewitness accounts are pretty rare. Instead, what generally seems to happen is that a body is discovered, badly burnt but usually with very little damage to the surrounding furniture or even, sometimes, parts of the victim’s clothes. Observers of the scene then draw their own conclusions, some more rational than others, as to how the burning occurred.

Possibly one of the most famous cases like this is that of Henry Thomas. He was a 73 year-old man whose remains were discovered in the living room of his council house in South Wales in 1980. His entire body had been incinerated, leaving only his skull and a section of each leg. Bizarrely, sections of his socks and trousers were relatively unscathed, as was half of the chair he’d been sitting in, and most of the rest of the room except for some smoke damage.

Could ball lightning cause people to catch fire?

Could ball lightning cause people to catch fire?

There are various theories to explain this kind of gruesome discovery, from ball lightening, to flammable intestinal gases (namely methane, which is the same gas in your kitchen cooker), to acetone building up in the body. The most famous, and probably best accepted of the more scientific theories, is ‘the wick effect‘, popularised in a BBC QED documentary in 1998. This idea likens a clothed human body to a candle, but with the wick (clothes) on the outside. The person’s fat is the fuel source, and the theory goes that the person’s fat melts and burns slowly, like a candle, over a period of several hours. The burning is very localised, which explains the lack of damage to the surroundings. Police forensic officers decided that Henry Thomas’s death was most likely an example of the wick effect in action.

It is often the case that apparent SHC victims are elderly, have low mobility due to illness or obesity, and are smokers (in other words, had a source of ignition in the vicinity). The logic goes that they are somehow incapacitated, perhaps a heart attack or stroke, perhaps excessive alcohol consumption, drop their cigarette and burn slowly.

But there are cases where the burning seemed to be a lot more sudden, and even a few where someone else was on the scene. For example, the most recent (suspected) case of spontaneous human combustion in the UK was that of Jeannie Saffin, who died in 1982. She was a 61 year-old woman, but had the mental capacity of a child due to birth defects. She was sitting with her father in the kitchen of their family home. He wasn’t looking directly at her when she caught fire but, according to his account, something caught his eye and he turned to find her suddenly ablaze. He and his son-in-law put out the fire using water, and then called an ambulance. She eventually died in hospital despite treatment. The coroner refused to accept the suggestion of spontaneous human combustion saying there was “no such thing”, and recorded an open verdict.

Jeannie Saffin’s case clearly wasn’t an example of the wick effect; it happened too fast. As far as I can find out, no one has ever really been able to explain why she caught fire so suddenly. She was in a kitchen, and kitchens do typically contain sources of ignition. Perhaps something went unrecorded: matches, alcohol, use of a gas oven. But even if it did, why did she burn so quickly and so violently? Flammable clothing perhaps? The truth is, we will probably never know.

Not too much now.

Not too much now.

Searching around I found other examples, but in every ‘sudden’ case I found the victim was in close proximity to something flammable or something that could, conceivably, provide a source of ignition. Or both. In particular, there are several cases of apparent SHC happening in cars. Usually a fire crew has investigated and found no traces of petrol in the wrong place. But… this seems like too much of a coincidence to me. Petrol is extremely flammable – could a small trace be present, perhaps from filling up the tank? If something were to ignite it, it could cause other things to burn, like synthetic fibres or, an even more likely culprit, hair products like gel or hairspray. Hair coated in product can burn really quickly. It doesn’t entirely explain every detail, but then it’s hard to know what is and isn’t an accurate account in these cases.

The truth is that spontaneous (if that really is an appropriate adjective) human combustion remains a bit of a mystery.

Just be careful around those jack-o-lanterns.

—

† I may be misquoting, it was a long time ago, but I’m sure I’ll be forgiven if I am.

Clever Chemistry Cupcakes

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On Friday I had my last lesson with some lovely year 13 (upper sixth in old money) students who were about to go on study leave. They bought with them the rather fabulous cupcakes in the photos below. Now, I could talk about baking chemistry, but I’ve done that before so I won’t repeat myself. However as you can see they did a rather lovely job of icing. In fact I think they’ve gone above and beyond in covering a broad spectrum of chemistry. It’s really quite a nice revision aid. Perhaps eating the cake will somehow cause the information to be absorbed more effectively, who knows…

Chemistry cupcakes part 1...

Beats flash cards huh?

So in their honour, and just in case you can’t make any of the symbols out, I’m going to attempt to explain what each one is (by the way, links go to Chemguide, an excellent source if you need a bit of last-minute information):

From left to right:

But wait, there’s more!!

Chemistry cupcakes part 2...

Are you full yet?

Left to right again:

So there we go, aren’t they great?  Good luck to this lovely lot, and to all the other students out there about to tackle their final A2 exams. Wishing you all the best for the future! 🙂

Good luck!

Good luck!

Physics meets magic: the Atheist’s Deck of Cards

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Deck of cardsFair warning to my usual readers, I’m deviating slightly from chemistry today. To explain why I’ll start with this admission: one of my very favourite things, other than chemistry naturally, is magic. I mean stage magic of course, I understand that the post of Potions Master isn’t actually a job option (and let’s just not mention the acromantula venom I’ve got stashed under the bed).

I’ve never had the patience for the endless practice necessary to learn to perform tricks myself, but I love watching stage magic and close-up magic. I’ve seen lots of magicians live, from local acts like Young and Strange to the much more-famous Paul Zenon, and right up to some of the big names like the brilliant Derren Brown. But my favourite act of all has to be the indomitable Penn & Teller.

Penn & Teller

The amazing Penn & Teller

I adore Penn & Teller. They are amazing. I’ve seen them twice now, in London and in Las Vegas. It’s necessary to make the Vegas trip if you want to see them perform their infamous bullet-catch trick. I imagine it’s tricky to get the firearms needed past the airport security teams these days, even if you are masters of sleight of hand.

Anyway, why am I talking about magic on a science blog? Well because this week I was listening to Penn Jillette’s podcast, Penn’s Sunday School (I recommend a listen, although possibly not in front of your elderly maiden aunt), and he was talking about a new bit they are about to include, or may have just included, in their show called The Atheist’s Deck of Cards.

Tex Ritter

Tex Ritter, without his deck of cards.

If you’ll excuse another apparent non-sequitur, when I was a kid we used to regularly drive to Germany. As you can imagine, it was a long trip, and one of the things I remember about it was a particular album of country music playing on the car stereo. I don’t know who the owner was, but someone had it on cassette and it used to go round and round until, I think, someone else had enough and forcibly removed it. As a child much of this went over my head, but to this day I still remember a couple of songs, one of which was Tex Ritter’s Deck of Cards.

This particular song, if you can call it a song, is about a soldier in trouble for apparently playing cards in church. He justifies his actions by explaining that his deck of cards is actually his bible, almanac, and prayerbook. The ace reminding him “that there is but one God”, the 10 reminding him of the ten commandments, the 52 cards reminding him of the number of weeks in a year, the total number of spots on all the card faces reminding him of the 365 days in a year, and so on. It’s really very clever. If that soldier came up with it on the spot he thoroughly deserved to get away with it; it certainly puts Blackadder’s Great Boo’s up to shame (although that was funnier).

Anyway, it seems I’m not the only one to have this song lodge in their brain. Penn Jillette admits to being crazy about it. So much so that he and Teller have written, with the help of theoretical physicist Lawrence Krauss, a physics and magic version which they have titled The Atheist’s Deck of Cards.

As Penn says in podcast number 99 (I hope he doesn’t mind me quoting), it starts like this:

“A while ago Teller and I were sitting in the front row of a lecture by the theoretical physicist Lawrence Krauss. Suddenly Krauss looked down and said: ‘Teller, you’ve been fiddling with that deck of cards since I began speaking. Do you find me so dull that you have to amuse yourself with trivial tricks and manipulations?’ Teller stood up and addressed Lawrence and the entire audience and said: ‘not at all Dr Krauss. I’m listening to every word you say. I don’t carry a pad of paper, or a cellphone, but as a magician I always have my deck of cards with me. And I use that deck and my knowledge of magic to take notes. Please allow me to recap what you’ve covered so far.’ At that point Teller fanned the cards out and said: ‘you’re a well-known atheist, and as I look over the faces of the cards I notice there’s no God among them. The universe of my deck, like the universe of your speech, contains Kings, Queens, billions of number combinations, even a couple of jokers, but no God can be found.'”

They then get properly into the physics, with:

“And the four aces remind me of the four fundamental interactions in nature. The ace of diamonds always reminds me of electromagnetism. So the ace of hearts is gravity. The strong force is the ace of spades, so the ace of clubs is the weak force. Now someday there may be an accepted unified field theory and all of these cards will be of one suit, but until then the four aces remind me of the four fundamental interactions. Electromagnetism is the interaction responsible for practically all the phenomena encountered in daily life.”

“And these six cards remaining remind me of the cosmological constant. It’s an amazing constant. Even as space gets bigger, the energy density remains the same. Please allow me to demonstrate.”

All the while, as Penn recites this amazing monologue (which must have been utterly horrendous to memorise to the level of word-perfectness required), they are doing fantastic card tricks to illustrate the story. Making cards disappear, making (I imagine) all the cards appear to be the same suit, and so on.

Now of course I haven’t seen this bit, because I can’t just pop over to Vegas and pick up Rio tickets, but doesn’t it sound utterly AMAZING? Penn was worrying that it might be too much, but I predict that his audiences are going to completely love it. I love it and I haven’t even seen it.

So now my only problem is how to get to Vegas. Or failing that, can I persuade Penn and Teller to send me a DVD? Or at the very least, the script? Please?

And then, of course… perhaps we should start work on The Chemist’s Deck of Cards?

Moronic acid, windowpane, curious chloride and other silly substance names

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My recent post on arsenic got me thinking about silly chemical names.  There are, in fact, asilly atom number of compounds that contain arsenic that chemists have clearly named with great glee.  In fact it seems quite likely that some of them were even deliberately synthesized purely for the opportunity to get a naughty-sounding word into a chemical name.  But it goes way beyond arsenic: there are many, many molecules with quite frankly ridiculous names.

So with such childishness in mind, here’s my top ten of silly substances:

1.  Adamantane
I have to confess that when I first met this molecule at university I though the lecturer was adamantanejoking.  He wasn’t, this rather odd-looking cycloalkane is a real molecule.  It’s existence was first suggested in 1924 but it wasn’t actually made until 1941 – either way it preceded the 1980s pop star by some years.  The arrangement of the atoms in adamantane is like those in diamond, and that’s where its name comes from: the Greek adamantinos, meaning relating to diamond or steel.  In itself adamantane doesn’t have many uses, but its derivatives are important in drug synthesis.

2.  Megaphone
YES THERE REALLY IS A MOLECULE CALLED MEGAPHONE!  It gets its name not because it’s loud, but because it’s extracted from the plant Aniba megaphylla.  It’s interesting because it has been shown to inhibit the growth of certain tumour cells.

3.  Arsole
Please remember I didn’t come up with this, it’s a real molecule.  It contains, not arsolesurprisingly, arsenic and has the rather simple formula of C4H4AsH in, ho ho, a ring-shaped structure.  It’s actually never been isolated experimentally itself but, and this just gets better and better, a class of similar molecules called arsoles have been investigated.  Arsole bonded to a benzene ring would be called benzarsole.  Ok I’ll stop now.

4.  Moronic, traumatic, erotic and diabolic acids
Not one, but a collection of acids (and there are more than these four with silly names, but we don’t want to be here all day).  The ‘ic’ ending for organic acids has provided rich fodder.  Moronic acid rather boringly gets its name from the Mora excelsa tree, from which it was isolated.  Traumatic acid actually gets its name from what it does – it’s a wound hormone that helps plants to repair damage.  Erotic acid is really called orotic acid, but it’s been misspelled so often that erotic acid has become an accepted name for it.  Diabolic acids are actually a class of compounds, named after the Greek diabollo, meaning to mislead, since they were particularly difficult to isolate.

On the subject of acids, honourable mention must also go to the wonderfully-named triflic acid, which sounds like something you might extract from a triffid.  It’s not obviously, but it’s still quite interesting stuff, being one of the strongest acids.  In fact it’s a superacid, which makes it sound a bit like a superhero’s deadly nemesis.

5.  Cummingtonite
This sounds like the sort of tortured name someone might invent for cocktail happy hour, but in fact it’s a greeny-brown mineral with the rather spectacular formula of (Mg,Fe)7Si8O22(OH)2.  It gets its name from the town of Cummington, Massachusetts (wouldn’t you love to live there?), where it was first discovered in 1824.

6.  Windowpane FSTRANE
You have to love this one.  The molecule actually looks like a child’s drawing of a window.  It’s more properly called fenestrane (from the Latin word for window, fenestra), and while it’s never been synthesised itself a version with a corner carbon missing has been made and, naturally, goes by the name ‘broken window’.

7.  Curious chloride
Isn’t this just the cutest thing?  Someone should write a children’s book.  CmCl3 is more properly named curium trichloride but ‘curious’, or ‘curous’, is the trivial name for curium compounds.  A concentrated solution of curious chloride would be radioactive enough to boil itself if left alone.  Maybe not so child-friendly, then.

8.  Welshite welshite
Funny to us Brits, probably meaningless to an American, this reddish-black mineral was named after Wilfred R. Welsh, an amateur mineralogist from New Jersey.  He was a president of the Franklin Mineral Museum and this mineral was named in his honour by one of his former students.

9.  Fucitol
This sounds like something a student might say at the end of a long Friday in the laboratory, and funnily enough it’s also an alcohol.  It’s officially known, more boringly, as L-fucitol, 6-deoxy-L-galactitol.  It gets its silly-sounding trivial name because it comes from fucose, which is found in a North Atlantic seaweed with the Latin name Fucus vesiculosus (and the almost equally brilliant common name, bladderwrack).

10.  DEAD Diethyl-azodicarboxylate
What else could I end the list with?  DEAD is the apt acronym for diethyl azodicarboxylate.  This wonderful orange stuff is rather unstable: it’s shock sensitive, light sensitive, toxic and a possible carcinogen and will explode violently if its pure form is heated above 100 degrees C.  When it’s mixed with acid and triphenylphosphine the result is called DEADCAT – brilliant.  DEAD used to be used in quite a few chemical syntheses, but thanks to its impressive list of safety hazards these uses are declining.

For even more silly-named molecules, see http://www.chm.bris.ac.uk/sillymolecules/sillymols.htm – what’s your favourite?

My Pointless addiction

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I love the TV show Pointless (5:15pm weekdays on BBC1, and I didn’t have to look that up).  I am an unashamed addict.  For those that have never watched, they give 100 members of the public 100 seconds to answer questions, and the aim of the contestants is to name the most obscure answer provided in particular category, in other words the one the fewest people answered correctly.  As I write, the current topic is TV Armstrong 4elements of the periodic table.  They use the periodic table quite a bit – they must have a chemist in their team of research elves (it’s sort of implied that the lovely Richard Osman makes up all the questions, but I’ve always assumed he has at least some help).

Naturally I can name all the answers in this round.  They are: sulfur, copper, mercury, sodium, fluorine, nitrogen and barium.  Yes all right, I’m showing off now.  I reckon nitrogen might be the lowest, since its clue is about its boiling point.  We’ll see in a bit…

I’m actually rather comforted by some of the high scores.  34 people out of 100 recognised sodium and 39 barium.  54 got copper and 80 mercury.  There is hope for the nation after all.

Ah, it turns out that fewer people knew it was a compound of fluorine in toothpaste.  Heston Blumenthal and his habit of chucking liquid nitrogen around has a lot to answer for.  It was close though, the second lowest score.

Now for the next round.  Now I’m helped here by the fact that they’ve included atomic numbers, else I’m not sure I’d have got the one referring to album sales.  I’m vaguely aware that gold and platinum albums are possible (and silver?), but I’m clueless as to the sales numbers required.  Ok: oxygen, zinc, platinum, magnesium, bromine, radon and carbon.  I reckon the lowest is going to be… um… well probably platinum.

And while I wait, thank you Richard for stating the correct spelling of sulfur in two episodes now.  I’m always arguing with people about that.

Hmm, I couldn’t have been more wrong.  Platinum was in fact the second highest answer on the board after oxygen.  As Alexander Armstrong pointed out, I suppose that’s really about your knowledge of the music business (an area in which I am pitifully uninformed).  The lowest score was bromine.  I should have realised.

Oh dear the next round is on English Football.  I’d be straight out.