How to Spot a Psychopath

Development of mutant healing factor not guaranteed

26 April 2012 — dan

A reader writes:

I was wondering if you'd heard of the appearance of some pseudosciencey Power Balance-esque magnetic bracelets in the new Avengers movie - and that the bracelets are actually for sale for $200 (!), endorsed by Paramount and Marvel Comics.

I first read about this on a Hijinks Ensue comment post. As a fellow skeptic and longtime reader of your blog, I thought I'd alert you to this scummy product placement.

n

Yep, the Limited Edition Colantotte Magtitan Neo Legend really does seem to combine five forms of pseudoscience, doesn't it?

It's not at all like the admittedly worthless Power Balance wristband, though. Power Balance and similar "hologram" or "ionised" bracelets don't have any identifiable physical properties, or effect on users, that a non-"energy"-enhancing silicone rubber wristband doesn't have, as long of course as the user believes their bracelet is special.

But the Magtitan Whatever Edition has magnets in it. And, as we all know, magnets can do anything.

This is sort of like the problem with debunking psychics, where the true believers say "OK, Mr A proved to be a fake, but Ms B must be genuine!", and then move on to Mr C, Ms D and so on as each new prospect is debunked until the skeptics run out of un-wristband-enhanced energy. Nobody can ever prove that every single "quantum" talisman, psychotronic money magnet, mobile-phone antenna-booster sticker, ultrasonic mosquito repeller, magic electricity saver or miraculous fuel additive is a scam, so chronic credophiles always have a new thing to believe in. And finding a new thing to believe in takes a lot less time than proving the thing doesn't work.

I agree that this product placement is weird, though. You'd think it'd be counterproductive.

"Do you find it entirely plausible that part of the Hulk's transformation invariably includes the manifestation of a pair of indestructible purple pants? Have you never wondered how Tony Stark can pull hundreds of gees and take hits like Superman without ever being turned to red chunky salsa inside his armour? Then do we have a health product for you!"

Posted in Scams, Science. Leave a Comment »

"MY COM-PO-NENTS ARE FUL-LY COM-PAT-I-BLE WITH LE-GO!"

25 April 2012 — dan

Among the greatest of the problems facing modern humanity is, I scarcely need say, the fact that there is no satisfactory way to make a Lego Dalek.

Well, not a little one, anyway.

Source: Flickr user Oblong

This fellow is quite magnificent, but...

Source: Flickr user lloydi

...I think something in excess of half-scale.

This smaller one's not bad either...

Source: Flickr user Neil Crosby

...(you'd want it to be good, since it's at Legoland), but the approximations are already creeping in.

Get just a little smaller and you're reduced to something like this...

Source: Flickr user pasukaru76

...of which the most one can say is that it's identifiable as a Dalek, if you squint.

If you want a Dalek roughly to scale with Lego minifigs, you're reduced to something more like...

Source: Flickr user Kaptain Kobold

...this.

I don't care how many of those you've got...

Source: Flickr user LostCarPark

...they're just silly.

Although I do give Kaptain Kobold credit for this one.

Source: Flickr user Kaptain Kobold

(Safe for work. NOT safe for work.)

These...

Source: Flickr user LostCarPark

...are silly too.

Source: Flickr user jjackowski

Nope.

Source: Flickr user pasukaru76

And this is a nice bit of microscale minimalism, but still not what you'd call faithful to the source material.

But, gentle reader, there is a solution. Though it carries a price - a price you may adjudge too high.

If you want a minifig-scale Dalek that actually looks like a Dalek, you can have it. All you must do is... I fear even to say it... is buy off-brand Lego.

I feel so dirty.

But just look at these little buggers.

Daleks! Made out of Lego-compatible blocks! Properly built up out of pieces, too, not just single-piece lumps!

Each Dalek breaks down into six major pieces and three minor ones. The baseplate, the skirt, the sucker-and-gun section, the shoulders, the neck and the head are all separate and about as Lego-compatible as it's possible for them to be, given their shape. The minor parts are the sucker, gun and eyestalk, all of which fit in holes too small for any other Lego piece or sub-component I can think of right now. The three minor pieces all have to point straight out, not swivel, but the head turns. (So do the shoulder and neck pieces, but not the sucker-and-gun section, which was never able to turn on-screen either, until 2005.)

Thanks to all of those pieces, if you want to make a Special Weapons or Emperor Dalek, it's no problem. The skirts also, of course, provide the perfect plinth for the Lego Davros torso of your choice.

(You can also just stick the head piece on top of a minifig's head and get something that doesn't really look like, but is no more ridiculous than, those preposterous helmets worn by the Daleks' human underlings in Resurrection of the Daleks.)

These not-actually-Lego Daleks are made by Character Options, who make various other licensed action figures and playsets and such. (All eleven Doctors? Fifty quid as action figures, twenty quid as pseudo-Lego.) Their "Character Building" brand has a variety of Lego-compatible Doctor Who sets, mostly just minifig-scale Doctors and companions and monsters. I bought the "Dalek Army Builder Pack", which gives you five red Daleks and nothing else. There are yellow and white Daleks in other sets, and Character Building also has one of those gashapon deals going where you can spend two pounds on a minifig from, thus far, two series, but not know what one you're going to get. You can get a blue Dalek that way if fortune favours you; any other colours, you're thus far going to have to paint yourself.

(You're also going to have to break out the paint if you want the Dalek bumps on the skirts to be a different colour from the skirts. In this scale the bumps are only about four millimetres in diameter, so it's not surprising that Character Options, um, opted, to leave them the same colour as the skirt.)

The Character Options sites lists the Army Builder Pack for £9.99, which is around $16 Australian or US, as I write this. I got mine on eBay for only £10.70 including delivery to Australia from this UK seller (here on eBay US, here on eBay Australia), but they don't have any more for sale as I write this.

There are plenty of other eBay sellers who do have stock, though; this search ought to find them all. The cheapest ones are all selling one individual Dalek parted out from a kit; the cheapest Army Builder set as I write this is £7.99 plus postage. There are plenty of sellers on Amazon, too.

The Character Building Daleks do have one flaw, though, which may be even more of a problem than the fake-Lego problem:

They look a little like Teletubby Daleks.

The Teletubby, a.k.a. Power Ranger, Daleks are the ones last seen on TV in 2010's Victory of the Daleks, when the Doctor was, for once, conclusively outmaneuvered by his enemy, and tricked into reincarnating these purestrain "New Dalek Paradigm" monsters.

(And, incidentally, there were also Spitfires in space.)

I thought Victory was a good episode (and quite funny, which counts for a lot), except for some industrial-grade schmaltz involving an android. But the new colour-coded Daleks at the end, each with their own more or less peculiar name, were not well received by the fans. Especially the... really enthusiastic fans.

The New Paradigm Daleks are big and shiny and brightly coloured, and have a great hunchbacked extension on the rear of their bodies, which gave me the impression that the props had for some reason been designed to have two human operators inside. I'm sure that isn't actually the case - these were Daleks in 2010, not Jabba the Hutt in 1983 - but there the huge lump is, or at least was.

Perhaps the Teletubbies are never coming back. Perhaps they're coming back but along with the older kinds. Who knows. (Free plot idea: The new ones are fat because they are pregnant with a much better design of Dalek.)

Anyway, these little Lego-ish ones do look a bit like them. But they're clearly not the same. The hump is less pronounced, the head isn't positioned way forward on the shoulders, the weapon-and-sucker section doesn't bulge out from almost vertical sides, and they've got that odd zipper-like grille thing on the back, but who cares.

I don't think they quite match any Dalek that's ever been seen on screen, but the Dalek props have, over the years, also failed to match each other in various ways, even if you've managed to erase the Peter Cushing Dalekmania movies and their Daleks armed with fire extinguishers from your mind.

(The New Paradigm Daleks stand significantly taller than the old ones, too; the Character Building ones are about a head taller than a standard minifig with no hat on, but are I think about the same height as the Character Building pseudo-minifigs.)

So if your interest in the racial purity of Daleks is only exceeded by their own, then you may consider these ones unacceptable. But they're really not very Teletubby-ish.

And, c'mon. Lego-compatible Dalek parts!

Haven't you always wanted the Doctor and a companion to be desperately hiding as the sound, tic-tic-tic-tic-tic-tic-tic, of robotic spider-legs approaches, and stops, and then a spray of baleful blue eye-lights spotlight them and the Mark V Travel Machine rears up, twenty feet high, dozens of its blackly shining sense globes irising open to extrude claws and tentacles and saws and injectors and suction feeders and flensers and écraseurs and deglovers, even as its battery of far-too-merciful gunsticks retract, and in a voice that breaks windows it SHRIEKS-

...well, actually these things probably won't greatly help you make that.

But if you let your kid at 'em, imagination ought to fill the gaps.

Posted in MiniReviews, Nerdery, Toys. 4 Comments »

Electrochemical Spuds Of Death

24 April 2012 — dan

A reader writes:

Hello there Mr. Dan. I stumbled across your site whilst googling "can you get hurt making a potato battery". Yep, I googled that.

I (clearly) know little about the electronics/cathode/anode world... but could answer lots of questions about other things non electrical. :)

In planning my son's birthday party, I am considering a potato battery station (sounds odd for a party, but trust me, it fits with the theme).

I have seen several Youtube videos with instructions and examples, some done by children. My main question before I go buy a bag o potatoes and seek out the copper wiring aisle of Walmart is: Can children be hurt doing this? Yes, us grown-up types will be there too, but is there anything I should be concerned about?

Partying Mom

It is theoretically possible to kill yourself with potato batteries, but the chance of a kid managing to achieve this is much, much lower than the chance that one of them will fall over and crack his/her skull in your bathroom, and you probably won't lie awake at night worrying about that.

I could just leave it at that, but of course I won't. This is because I think an understanding of the basics of electrochemistry, which is what potato batteries are all about, is something that all modern humans should have, even if they never put it to use.

You should know why it's warmer in the summer (it's surprising how many people incorrectly say "because then we're closer to the sun", which, even if it were true, would make summer happen at the same time for both the northern and southern hemispheres...), you should know how tax brackets work, and you should also know the basics of the technology that envelops modern humans so completely that we hardly notice it at all.

Sorry, didn't mean to lecture you. This is just something I'm rather passionate about.

Getting back to potato batteries: The power output of an individual potato, or lemon, or what-have-you, "battery" is extremely low, which is why there are few-to-no things you can power from one spud with two pieces of dissimilar metal in it.

"Battery" is in quotes up there because one tuber and two bits of metal are a single electrochemical "cell"; technically, it's not a "battery" unless it has more than one cell in it. (So, of the things sold in the supermarket as "batteries", AAs and Cs and Ds are cells, but 9V or 6V batteries, composed of six and four 1.5-volt internal cells respectively, really are batteries.)

The open-circuit voltage of any electrochemical cell is determined by the electrode potential of the materials you use for the electrodes. If you build the usual kind of potato battery with copper and zinc electrodes (like, a copper or copper-plated coin, and a zinc-plated galvanised nail), each cell will have an open-circuit voltage of 1.1V, but a current capacity into a short circuit of less than a milliamp.

The larger the surface area of the electrodes, the higher the current capacity will be. But even with really big electrodes you'll probably only get half a milliamp into a short circuit - and the more of the cell's current capacity you use, the lower its output voltage will be.

(For comparison, I just grabbed a rather old but unused off-brand "super heavy duty" - meaning, carbon-zinc, not even alkaline - AA cell out of my Drawer Of Many Batteries, and it still reads more than 1.6 volts open circuit, with a short-circuit current capacity of more than 1.5 amps. Here's a PDF datasheet for an Energizer carbon-zinc AA; they've got a sub-site devoted to these things.)

If you make multiple potato batteries and put them in series and/or parallel, you can increase the voltage and/or current capacity of the whole battery, respectively. Two cells in series (both of which can be stabbed into the same potato; just connect the copper of one cell to the zinc of the next) and you get 2.2 volts open circuit and the same miserably tiny current capacity. Two cells in parallel, and you get 1.1 volts but double the current capacity. Six cells, wired up as series strings of three with the two strings in parallel with each other, and you get 3.3 volts and double current capacity. And so on.

(Many people seem to find the concept of series and parallel circuits tricky to grasp. It's another of those bedrock pieces of information about the world that I urge everyone to learn, though, because it explains a great deal of everyday electrical things. Why does one bulb dying in a string of old Christmas lights kill the whole string? Because they're ten or twenty 12V bulbs {depending on your local mains voltage} wired in series to connect directly to the mains. Why, in contrast, can you have a couple of things turned on and a couple of things turned off all plugged into the same powerboard and have everything work? Because the powerboard's outputs are in parallel!)

Getting back to your actual question, this is how you could, if you tried very hard, kill yourself with a potato battery. 30 milliamps across the heart has a pretty good chance of stopping it, and even lower currents have upon occasion been fatal. Kids might be more susceptible, too; I don't know.

Even sweaty skin is a good enough insulator that sundry low-voltage current sources aren't dangerous - grab the terminals of a 12V car battery with bare wet hands and you probably won't even feel a tingle, though a tiny current really will be flowing through your arms and across your chest. But if you stab probes into yourself, into your hands or preferably into your chest right on either side of the heart, then an array of potato batteries big enough to deliver tens of milliamps really could, if connected to the electrodes, kill you.

(One reason why high voltage can be especially dangerous is that it can spark a hole right through the skin, giving it access to your wet salty conductive innards.)

Given, of course, that this particular means of death starts out with stabbing yourself, you could simplify the process by just stabbing your heart directly.

Hence: Not worth worrying about.

(There's also an outside chance that you could poison yourself by eating a potato or lemon or whatever that's been used as a battery for a while, because it'll now be contaminated with various metallic salts. It probably wouldn't do more than make even a small child slightly ill, though, presuming he or she somehow managed to choke the vile-tasting thing down. This situation is even less likely to happen than chest-stabbing, unless you use some particularly delicious fruit instead of a potato or lemon.)

The great problem with potato-battery demonstrations in the past was not, of course, kids somehow killing themselves, but that it was very difficult to do anything with the extremely feeble output of such a battery. Turning even a tiny motor, or lighting even a grain-of-wheat incandescent bulb, was impossible without a ridiculous number of cells. Getting a feeble glow from a grain-of-wheat bulb rated for 12 volts and 80 milliamps could perhaps be done with as few as 50 potato cells, though I suspect you'd need a hundred or more.

So potato batteries usually ended up doing something lame like powering a pocket transistor radio with a piezoelectric earpiece, which is a feat that you can more impressively achieve with no battery at all.

Today, you could similarly fail to impress the youngsters by potato-powering one of those little LCD clocks and kitchen timers that're meant to run from a couple of button cells. Two or three potato cells in series might, at a stretch, be able to run one of those. A far better target, though, is lighting a light-emitting diode (LED).

A modern high-intensity red or amber LED will only want about two volts and a couple of milliamps to light dimly, and will be quite impressively bright at only 10mA. Ten parallel strings each containing two potato cells ought to be enough to give a pretty bright light, and each two-cell "string" could be only one potato.

Here's a red LED...

(image source Flickr user trvance)

...just barely glowing from only three copper/zinc lemon cells in series...

(image source Flickr user s8)

...and here's an excellent example of multiple cells in one lemon...

(image source Flickr user s8)

...which works extremely well because it's cheating, and using a simple four-component circuit (counting the LED) called a "Joule Thief", which I learned about years ago on the excellent Web site of the inimitable Big Clive.

I recommend you provide sufficient spuds and/or lemons, electrodes and alligator-clip leads to make lots of cells, and also provide a grab-bag of water-clear high-intensity LEDs so the kids don't know what colour they've got until they get it to light up.

A lot of LEDs will not cost you a lot of money. I find it mind-blowing that the going price on eBay for a pack of a hundred mixed waterclear high-intensity LEDs has, for some time now, been under five US bucks, delivered. I suggest you get 5mm LEDs, not the 3mm ones that're the absolute cheapest, because the smaller ones are a bit fiddly even for kids' hands.

(I don't actually need any more LEDs, but I just felt morally obliged to buy this hundred-5mm-LED pack, from this seller, for $US2.99 delivered. At this price you could use these things, which were a miracle of the age in the 1970s and have for years now been revolutionising a significant portion of the lighting industry, as notice-board pins. They are literally cheaper than thumbtacks. Even the ones with three different-coloured dies and an invisibly minuscule controller chip built in cost damn close to nothing.)

You should play with this stuff yourself before the party, so you can introduce the kids to the series/parallel idea, and help them if they don't know to chain the cells nose-to-tail (copper to zinc or zinc to copper, not copper to copper or zinc to zinc), and also see which way round you have to connect the LEDs to make them work. (They're light-emitting diodes; they only work one way around. Long leg positive.)

It would also be a really good idea to get the finest, cheapest digital multimeter eBay has to offer, so you don't have to rely on licking the ends of wires to estimate how many volts your potatoes have managed to make. Every home should have a crappy ten-buck yellow plastic multimeter; you may not use it often, but it can be very handy at times. (Put it in the kitchen drawer with the screwdriver, the hammer, the random screws and washers and the polycaprolactone.)

Depending on age and disposition, the kids may figure this all out for themselves, of course. LEDs only work one way round, a battery setup that'll light a 1.8V red LED probably won't light a 3.6V blue or white one, a setup that'll light a blue LED may very satisfyingly turn a red one into...

Dead LED

...a friode, you can series- and parallel-wire LEDs as well as batteries...

While you're shopping for quantum-physics miracles on eBay for three cents each, you could add a couple more things that used to be super-tech and are now super-cheap: Lithium coin cells, and rare-earth magnets.

2016 (20mm diameter, 1.6mm thickness) and 2032 (3.2mm thick) coin cells aren't as cheap as LEDs; if you buy them in a supermarket or pharmacy you can pay dollars for one. Again, though, just hit eBay and you can find fifty for less than 15 US cents each.

Rare-earth magnets can be even cheaper. If you restrict this search to Buy It Now items more suited to the impatient, you can get twenty 8mm-diameter 1mm-thickness neodymium-iron-boron disks for less than ten cents each; hundred-packs drop it to about seven cents apiece.

Why am I suggesting you buy these items?

Because you can light an LED by just pressing its legs to either side of a coin cell...

(image source Flickr user spike55151)

...and if you put LEDs (preferably diffused 10mm ones, but any with legs will work), coin cells and magnets together, you get...

(image source Flickr user c3o)

..."LED throwies".

(image source Flickr user chopsueyphoto)

Which are easy to make, and awesome.

Psycho Science is a regular feature here. Ask me your science questions, and I'll answer them. Probably.

And then commenters will, I hope, correct at least the most obvious flaws in my answer.

Posted in Electricity, Electronics, Psycho Science. 13 Comments »

All I do is drink and wee, I'm gonna live forever!

18 April 2012 — dan

A reader writes:

Seeing lrwiman's comment on your post about how you can't lose weight by eating ice reminded me: Do you really need to drink eight glasses of water a day?

I guess it actually depends on who "you" are, how big or small, and how much you sweat and so on. Is eight 8-oz glasses just a one-size-fits-most amount for everyday urban humans?

Lana

There is no scientific basis for the "eight glasses a day" idea.

Eight eight-fluid-ounce glasses add up to, of course, 64 fluid ounces, or about 1.9 litres. That is rather a lot. If you're an office worker, you are very unlikely to need that much water (or equivalent other liquids, though the people who support the eight-glasses thing often say that no beverage other than water counts at all) to be perfectly hydrated. If you're a labourer in a hot climate, though, you're going to need a lot more than eight glasses.

(See also, people hiking in the desert who don't realise that you need to drink a lot more water, and keep your electrolytes up, when you're exercising in high temperatures and low humidity.)

Unless you drink a really amazingly large amount, it won't do you any harm to drink more water than you need, if you're not concerned about the amount of time you spend in the bathroom. 1.9 litres over several hours is well below the level needed to cause water intoxication in an adult, unless your kidneys are in bad shape.

Note that your total water intake can very easily be three or four litres a day, because other beverages, and water contained in food, count towards it as well. The eight-glasses people usually warn against consuming water when it's mixed with other substances that reduce its net hydrating effect, like caffeine or alcohol, which are both diuretics.

As usual, though, the dose makes the poison, or in this case the diuretic. A doppio ristretto or shot of Polish Pure Spirit is, like drinking seawater, going to have a net negative effect on your hydration. But if ordinary black tea didn't hydrate you, the entire British Empire would have died of thirst in about 1750. You can also remain well hydrated if all you drink is beer or weak wine; beer and diluted wine used to be staple beverages for whole cultures before the invention of sewer systems, when the available water was commonly contaminated with organisms that couldn't survive a few per cent of ethanol.

Drinking lots of water, often but not always this particular figure of eight glasses a day, pops up quite often as part of odd diet regimes.

The "Stillman diet", for instance, was an early low-carbohydrate diet which prescribed eight glasses of water a day in addition to any other fluid intake. And it sure did seem to pare away the pounds; it made a significant contribution to Karen Carpenter's downward trajectory of both weight and health.

Lorraine Day includes a lot of water-drinking in her list of things you can do to, immensely plausibly, cure yourself of cancer (unless of course you are Jewish, in which case she'd probably prefer that you die).

Back here on planet Earth, drinking water when you feel peckish can be a good dieting trick. Go ahead and throw in some ice cubes too, if you want something to (carefully...) chew on.

But apart from this, and from a few diseases for which drinking a lot of water is a treatment, there's no reason to drink water when you're not thirsty.

Psycho Science is a regular feature here. Ask me your science questions, and I'll answer them. Probably.

And then commenters will, I hope, correct at least the most obvious flaws in my answer.

Posted in Psycho Science, Science. 9 Comments »

Zero to Kafka in five minutes, or no money back

16 April 2012 — dan

OK, whippin' up the ol' Business Activity Statement for the first quarter of this year, tum te tum, run the special government BAS-management software and... it tells me I'd better renew my AUSkey certificate before it expires at the end of July.

Bit of an early warning, but OK, fair enough, off we go to the AUSkey site, which I leave open for a while as I enter stuff for my next BAS in the other special software that apparently a few other governments inflict upon their populace. (As is traditional with such things, this program likes to pop up dialog boxes telling you to enter a date for something, when you've entered data in some other field first, and then click on the date field intending to do the thing it is haughtily preventing you from doing until you click "OK".)

A few minutes later, I come back to the AUSkey site and click "login", whereupon it tells me my session has timed out and I have to go back to the home page, which is exactly where I already was.

What session? I don't have a session yet! I haven't logged in!

OK, argh, whatever, I log in again and it tells me I don't have the special AUSkey software which I thought I had but OK, again whatever, click the thing to download the software and... back I go to the home page again.

Go through that loop again until I realise that the site is attempting to tell me via mental telepathy that it does not support Chrome. Try Firefox instead, which to the government's credit does actually work and lo, now I do have the software that I installed whenever I went through this palaver the last time, and it doesn't even seem to need 283 updates since I last used it!

Righto, off we go, let's renew our certificate...

Hang on - there doesn't seem to be an option to do that anywhere.

Gee, could that perhaps be because the AUSkey does not, in fact, ever actually expire?

Why yes, that is the case.

Did the other program really tell me to update my AUSkey?

I quit it and run it again, and it doesn't say shit this time. I could have sworn it said I had to renew my AUSkey certificate but... now I... I just don't know.

You know, part of the reason why I wish Australia didn't have any submarines is that I'm not sure anyone's ever clearly explained what purpose they're expected to serve. (They apparently performed quite well in war games against the USA, which I'm sure will make all the difference if we decide to go to war with America. Or, marginally less crazily, with China, whose attack subs only outnumber ours 59 to six, not counting their entirely insignificant five nuclear ballistic missile submarines.)

Most of the reason, though, is that I don't think an institution that can create a system like this should be be allowed anywhere near explosives.

Posted in Money, Strange Tales. 3 Comments »

Save on cigarettes: Let someone do the smoking for you!

16 April 2012 — dan

A reader writes:

How dangerous is second-hand smoke, really?

The bans on indoor smoking that've taken over the Western world suggest that it's REALLY dangerous. Here in Australia you can no longer smoke even in a pub, so apparently second-hand smoke is worse for you than alcohol.

But it stands to reason that second-hand smoke is much more dilute than the smoke sucked out of the actual cigarette. I can believe it'd be a big health hazard if you were in some 1925 basement speakeasy jazz club with no ventilation and everyone smoking like crazy until you could barely see your hand in front of your face, but the thickness of smoke in a pub before the ban wasn't anything like that. It still made your clothes and hair smell like an ashtray, but that's just disgusting, not dangerous. Was it really that bad?

Richelle

Nobody knows exactly how dangerous second-hand smoke, or "passive smoking", is.

This is partly because of the, well, smoke screens, produced by astroturf organisations with the usual hilarious Decent People Opposed to the Decapitation of Adorable Ducklings names and the similarly usual giant piles of funding from the tobacco companies.

But it's also partly because there is, as you say, such a wide range of possible exposure levels.

And, I think, it's mainly because this is principally an epidemiological question, and epidemiology is a slippery area of study.

Given all these caveats, though, it's still clear, from numerous studies, that chronic exposure to second-hand smoke, even at relatively low levels, does significantly increase the chance of a non-smoker getting lung cancer and/or heart disease, plus a laundry list of other ailments that result from the inhalation of bad stuff.

If you're just waiting for a bus next to someone smoking and you get the occasional whiff of their Marlboro, nothing quantifiable will result. But being a child in a house with indoor-smoking parents, or regularly visiting a smoky pub as an adult, raises your lung cancer risk. Working in a smoky pub raises it more.

The important detail to remember here, though, is that the incidence of lung cancer in non-smokers is low. Only about 15% of all lung cancers are found in non-smokers, and most of those seem, once again within the statistical limits of what epidemiology can tell us, to have been caused by something other than second-hand smoke.

Chronic exposure to highly polluted air, for instance, will do it. A traffic policeman in Beijing, Mexico City or Ahwaz, Iran really ought to wear a gas mask, or possibly SCUBA gear, to work.

Numerous other kinds of smoke are also carcinogenic. If you work in a commercial kitchen with woks full of smoking overheated oil all over the place, that's bad. So is wood smoke; it may smell nice, but it's definitely carcinogenic. Incense is bad for you, too.

And then there's radon, a well-known danger in the USA, but almost completely unknown here in Australia, where very few houses have basements. You'll probably only have much exposure to radon if you're a miner, of if you spend a lot of time in a basement or other poorly-ventilated underground room dug into high-radon ground.

Sundry inhaled particulate matter is also bad news. This is another problem for miners, and various other industrial workers.

And there are lung-cancer-causing viruses, too.

And then there's asbestos inhalation, of course. But that's much more likely to cause the horrible-but-not-cancerous disease asbestosis than it is to cause mesothelioma.

Or you could just be fortunate enough to be genetically predisposed to develop lung cancer.

If you're a non-smoker and you can avoid all of these risk factors, then the chance that you'll get lung cancer - or, at least, that you'll get it a long enough before some other disease kills you of "old age" for the lung cancer to become an actual problem - is very small. Second-hand smoke exposure that doubles your risk of cancer sounds scary, but if there's only a one in ten thousand chance that you'll get it in the first place, then the doubling only raises it to a chance of one in five thousand, which probably won't keep you awake at night.

And the risk from different causes isn't necessarily cumulative, either. If you're a non-smoker who works without breathing protection in the Acme Smoke, Flame and Asbestos Dust Factory in the Land Occupational Health and Safety Forgot, and as a result have a 50% chance of getting lung cancer in the next ten years, then heavy exposure to second-hand smoke while you drink your way to amnesia on the weekends may only raise your cancer probability to 51 per cent.

Or it may do more. Again, epidemiology. Pick a hundred coloured marbles from the barrel of a million, try to figure out what colour the rest of them are.

Some scientists have argued that there's a somewhat unexpected public-health benefit from indoor smoking bans. Not only do they keep second-hand smoke out of the lungs of non-smokers, but the nuisance of having to go and stand outside with the rest of the Tobacco Lepers causes smokers to smoke less, and become healthier. The evidence presented for this is generally a reduction of hospital visits for smoking-related heart and pulmonary disorders after indoor-smoking bans go into effect, but this is yet more epidemiology, so it's eminently possible that the effect is from an entirely different cause, or smaller than it seems, or even nonexistent.

(Workers who hate having to go out into miserable weather to get their fix could easily, for instance, use their ten-minute break to suck down as much smoke as they possibly can in that time, to "stock up" and make sure that they can make it to the end of the day without cravings. They could, thereby, get a lot more crap in their lungs than if they were still allowed to have a leisurely cigarette or two at their desk.)

Psycho Science is a regular feature here. Ask me your science questions, and I'll answer them. Probably.

And then commenters will, I hope, correct at least the most obvious flaws in my answer.

Posted in Psycho Science, Science. 6 Comments »

DIY plastic update!

13 April 2012 — dan

If you're not in Australia, and not interested in polycaprolactone, this post is not for you.

Regarding that second criterion, though, I think pretty much everyone should be interested in polycaprolactone. I'd actually go so far as to say that every home should have some, even if you're not at all "handy". Just put it in that kitchen drawer with the screwdriver, the hammer, the dried-up epoxy and the random screws and washers.

Well, put it there when you've finished playing with it, anyway.

As I explained in this rambling 2010 post about the construction of...

...this, um, thing, polycaprolactone (which is sold under several easier-to-remember brand names) is a remarkable substance.

It can be moulded like rather sticky, see-through clay when hot (its melting point is about 60°C, but it's comfortable to handle at quite high temperatures, thanks to low thermal conductivity). When it cools, it turns into a smooth opaque white plastic about as strong, and tough, and easy to shape with other tools, as nylon. You can use it to do anything you could do with nylon, except of course withstand temperatures above 60°C.

And, unlike Sugru and various other putties and clays, polycaprolactone is reusable - just heat it up again. It'll also last forever on the shelf, and isn't even toxic, unless you set it on fire and inhale deeply.

You need hot water to soften polycaprolactone, but that's the only thing remotely dangerous or difficult about this stuff. Any child old enough to boil water without supervision can use polycaprolactone to make, fix or modify things. Because you can reuse it as much as you like, polycaprolactone is also an excellent do-it-yourself material for klutzy adults.

I spent a while in the 2010 post talking about where to find polycaprolactone, and what it cost. At the time, it wasn't hard to find the stuff here in Australia, but it was a bit expensive.

Now one Peter Edmunds, the proprietor of plastimake.com, is selling polycaprolactone locally for good prices.

Plastimake-branded polycaprolactone comes as the same white granules as pretty much every other brand. ("Friendly Plastic"-branded polycaprolactone is rather more expensive, but can be had in numerous colours and finishes.) As I write this, there are only two package sizes available from Plastimake; a hundred grams is $AU10 including delivery anywhere in the country, and 800-gram jars are $AU30, plus a flat fee of $AU10 delivery for as many jars as you like. They accept PayPal or credit cards for payment.

(Plastimake sell on eBay as well. Prices are the same.)

For comparison, Jaycar are still selling Polymorph-branded polycaprolactone in Australia. Their pricing starts at $AU11.50 for 100 grams - plus delivery, if you're buying mail-order - and drops to $AU8.95 per hundred grams if you're buying a kilo or more.

So if you're building your own Plastic Pal Who's Fun to Be With and want four kilos of the stuff - which is quite a lot, because polycaprolactone is only slightly denser than water - Jaycar will relieve you of $AU368 including road-freight delivery, versus only $160 delivered from Plastimake.

The UK eBay dealer (on ebay.com, on ebay.co.uk) that I recommended in the last post is still selling Polymorph-branded polycaprolactone, too. A kilo from them is £15.10 (about $AU23, as I write this) plus international delivery, which currently isn't specified for this largest size. If four one-kilo bags cost the same to send to Australia as four kilos worth of their 750-gram bags, though, the delivered price for four kilos would be about a hundred quid, or $AU153.

So Plastimake are ahead by a bit for small amounts - and if you've never played with polycaprolactone before, a hundred-gram bag will be plenty to give you the idea - and they charge about the same for large amounts delivered to Australian customers as the best eBay dealer I've found.

(If you want to place a really big order, you can also contact Plastimake for a further discount.)

Plastimake have a good site, too. In addition to the usual simple instructions, there's a big page of example projects, containing the various simple repair projects you'd expect, plus...

...eyelets for a rustic fishing rod...

...an item of headwear which many Australians will recognise...

...some quite impressive sculptures...

...and that most prosaic of all kitchen accessories, the form-fitted salami cap.

Plastimake also have a page of techniques, including colouring the plastic (as seen in the rose sculpture), making thin sheets, and alternative heating techniques.

Plastimake are brand new, so I suppose it's possible that Peter Edmunds will turn out to take your money and run, or something. Presuming he is not a rip-off artist or crazy person, though, there's really no excuse any more for Australians to remain polycaprolactone-less.

The stuff really is very fun, very useful and very easy to work with, and it tremendously appeals to the large penny-pinching lobe of my brain. It'll never go stale or dry out, and if you drill or carve something you've made out of it, you can collect and reuse even tiny shavings.

Highly recommended.

Posted in Handicrafts, Toys. 9 Comments »

Very very shiny rocks

12 April 2012 — dan

I couldn't really tell you which is my favourite item in my little element collection, but these recent additions certainly catch the eye.

(They're not actually all that recent, but I forgot to write about them until now.)

These are lumps of chromium. Solid chromium.

UPDATE: As requested in the comments below, here are a couple of little (silent) video clips of the chromium lumps in the sun, plus a chunk of crystalline silicon carbide and a couple of enormous cubic zirconias:

As undisputed king of the element-collecting hobby Theo Gray points out, chromium is commonplace in the modern world, but only in ultra-thin electroplated layers on other substances. There's no need to use more than a super-thin layer of chrome to make some car-part shiny, because chromium in air protects itself from corrosion with a hyper-thin oxide layer, sort of like aluminium, but more so. The chrome oxide layer, unlike the aluminium layer, is so thin that you can't even see it, so chrome looks freshly-polished all the time.

This stuff is actually so shiny that it looks fake, like rocks spray-painted silver and given an outlandish name in an episode of Star Trek. It feels more real when you pick it up, though, because chromium is only a little less dense than iron. It's also nonmagnetic, and non-toxic.

Various chromium salts are bad news and can be made accidentally in the home, by for instance using a stainless-steel object as the sacrificial anode for electrolytic de-rusting. But the metal itself is benign.

This is more than can be said for what's next to the chrome on my display shelf, the block of Wood's metal I cast in a Lego mould. Wood's metal has both lead and the more dangerous cadmium in it.

(See also, mercury. Metallic mercury is not good for you, but there's no reason to call out the men in moon suits just because you broke a fluorescent light. Organic mercury compounds, however, are very dangerous. Methylmercury, which can get into your body via contaminated fish, is rather nasty, and dimethylmercury is absolutely pure unadulterated gold-medal-winning death on a stick.)

I got my chromium, and a few other trinkets over the years, from eBay seller "The Mists of Avalon" (on eBay Australia, on eBay UK). From their name, you'd expect them sell a lot of metaphysical wank - and yes, they do! But right next to their "Wiccan/new age/spiritual/pagan" and "Healing/metaphysical crystals" categories, though, they've got umpteen science collectibles, and the listings for those items don't even contain the traditional fanciful explanations of the supposed effects of the periodic-table sample you're considering buying on chakras and meridians.

At the moment, Mists of Avalon seem to be the only eBay dealer selling these nice rock-shaped chromium lumps. They've got one listing for chunks not unlike mine, and another listing for "more than 10" bags of smaller lumps. (They've also got a listing for some chromium powder, but you probably don't care about that.)

There are a few other eBay dealers selling chromium, and other element, samples of one kind or another (on eBay Australia, on eBay UK). There's SoCal Nevada, for instance; I've bought a few sciency knick-knacks from them, too. They currently have one tiny crystal of chromium, and a couple of big machined disks of the stuff.

Theo Gray's pals RGB Research will be pleased to sell you a hefty cylinder of high-purity chromium, of the same standardised 35 by 55mm size as the tungsten and magnesium ones I've got (they don't have any of the big tungsten cylinders for sale at the moment, though) for the trifling sum of $US325 plus delivery.

EBay seller iannhart (on eBay Australia, on eBay UK) has a selection of 35-by-55mm cylinders too (including some tungsten ones!), as well as other shapes and sizes of chromium.

I'd hold out for the rock-shaped lumps, though; they really show off the bizarre nature of this substance. Tungsten doesn't look like much; its special characteristic is its extraordinary density, making it a plausible stand-in for plutonium.

Chromium is more like frozen latinum.

Posted in Nerdery, Science, Toys. 6 Comments »

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