How to Spot a Psychopath

A reader writes:

Could you build a tabletop cathedral out of sugar cubes?

What I mean is, of course you could build one out of soapstone, or soap, or wax, or whatever, but all of those are so strong you can get away with pretty much anything. Snow is weak but so light you can build a shelter out of it with no particular concern for architecture (though I once had an unpleasant surprise when it got warm overnight - "wait, should I really be seeing stars? and what's this weight on my legs?"). But sugar cubes are both heavy and fairly crumbly.

So could you build a cathedral of reasonable size and have to deal with similar engineering difficulties to those medieval stone-cathedral builders did?

Anne

Never having tried it myself, and not even having any sugar cubes in the house, I reckon you could build something pretty impressive with them. I think they may indeed be quite good analogues for unreinforced historic masonry, at around a 1:100 scale. And yes, this could be quite instructive, like the classic spaghetti-bridge exercise that also forces the architect to work with a material that behaves in small scale not unlike real construction materials at full scale, neutralising the square-cube law that tends to make models unrealistically sturdy.

(Look at this enormous model, for instance. It's held together with glue, which may reinforce the cubes significantly, or may not.)

The compressive, and tensile, strength of materials is defined in pascals, one pascal being one newton of force applied over an area of one square metre. Because of this rather large area, even quite feeble materials achieve strength scores up in the kilopascals (kPa).

If your sugar cube is, for the sake of argument, one centimetre square, its share of a 1 Pa pressure over a square metre would be only one ten-thousandth of a newton, which is the kind of pressure a marshmallow could withstand without visible deformation. Crank the pressure up to 10,000 Pa (ten kilopascals, kPa) and the sugar cube will be supporting a whole Newton, equal to a weight of about 100 grams under normal Earth gravity. This seems a plausible sort of strength for a sugar cube to manage.

The compressive strength of modern bricks and concrete blocks is up in the single-digit megapascals (or considerably higher, if the bricks or blocks don't have the usual holes through them); some natural stones are much stronger (granite manages around 200 MPa), but natural stone is likely to contain cracks and fissures that make the safe load limit considerably lower.

If sugar cubes turn out to actually be feeble, it might not actually matter that much, because the full compressive strength of masonry is surprisingly unimportant a lot of the time. You could build the Empire State Building out of stone, or possibly even ordinary bricks, and be in no danger of crushing the bottom blocks with the weight of the rest. That building would be spectacularly unsafe - even with a big reinforced concrete foundation to prevent it from subsiding into the earth, tilting and then toppling, things like wind stress and very minor seismic events could destabilise a giant stone tower very easily. (There is a reason why the longest-lived colossal stone structures in the world are approximately the shape that collapsing stonework naturally creates.) But compressive strength, at least, would not be a problem.

The centuries-old cathedrals that survive are, generally speaking, well engineered, but this is because they're the ones that didn't fall down. A lot did. Pre-scientific architecture was a trial-and-error, evolutionary process, in which people built things that looked as if they'd stay up, and then hoped that if the roof did fall in, it wouldn't be on a full Easter congregation. Sometimes there's evidence of a forced design review in the middle of a building's construction; the Bent Pyramid probably looks the way it does because it became clear to the builders half way through that they were making something too tall and pointy to stay up.

Very few collapses had anything to do with masonry being crushed by its own weight, though, except when some genius decided to use masonry like wood and, say, try to bridge pillars with a slab of stone (the ancient Greeks did this sort of thing quite often, which is why the Parthenon is as ruined as it is. There's a fabulous stack of broken lintels hidden inside the Great Pyramid, too; one broke, they put another one on top, it broke, they put another one on, that one burned down, fell over, and then sank into the swamp...).

Another great way to accidentally put masonry in tension is to put a darn great dome on your building, which will push down and out all around its base. Masonry must then be tricked into keeping force paths safely within the stone by contrivances like, for instance, flying buttresses. If you must have a huge dome, you either need a lot of these tricks, or a circle of very stout iron chain hidden inside the dome's base.

Getting back to sugar cubes, they're not actually all that dense, since they're a porous sintered aggregate of sugar particles (which is essential; a solid cubic crystal of sugar would look pretty neat, but you'd be waiting a while for it to dissolve in your tea). The density of sucrose is only about 1.6 grams per cubic centimetre in the first place.

So if we ballpark the mass of each once-centimetre cube as one gram, and set the ceiling supportable weight as 100 grams, we can stack 100 cubes on top of each other before the one at the bottom is under unacceptable strain. I've no idea how close these numbers actually are to reality, though, and there are no doubt considerable variations between different brands of sugar cubes (some of which are rectangular cuboids, not cubes at all), how they've been packed and otherwise treated, the same sugar cubes under different conditions (humidity, mainly), and so on. I invite actual experimental evidence from readers below; stack things on sugar cubes until they're crushed, and tell us how much weight your cubes can stand!

(In the above blather about historical architecture, any seeming brilliance on my part was actually just relayed from the author of two of my favourite books in the whole world, J.E. Gordon. The relevant book here is "Structures, Or Why Things Don't Fall Down", but "The New Science of Strong Materials, or Why You Don't Fall through the Floor" is also essential reading for anybody who, on reading those titles, realises that they don't really know why these unfortunate events do happen so seldom in the modern world.)

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.

A reader writes:

How does the "sugar rush" work?

My kids go crazy when they get candy and soda (which they usually don't, but I'm not so cruel a mom as to feed them carrot sticks on their birthday), and on the rare occasions when I drink non-diet soda I get about 15 minutes of energy followed by a miserable crash... but now my doctor tells me that the sugar rush doesn't actually exist at all, so it's all in my head. And my kids' heads, too, apparently.

The doctor's not very tactful, but he's always seemed pretty sharp to me. Is he right?

Judy

Yes, your doctor is right. There's no such thing as a sugar rush. Sugar is not a stimulant, whether it's glucose, sucrose, the High-Fructose Corn Syrup that continues to rain stickily down on the entire population of North America, or any of the other sweet-tasting whatever-oses.

If you eat something with simple sugars in it that all pass into the bloodstream quickly - glucose, which doesn't need any digestion, being the simplest of all - you can end up messing with your body's sugar metabolism. Presuming you're not diabetic, your pancreas will pump out a lot of insulin to cope with the sugar bomb and then, when all of that sugar is quite suddenly dealt with, your body may find itself with an insulin surplus and give you a low-impact version of diabetic hypoglycemia. Lots of non-diabetic people have symptoms like this; it's even possible to feel the shaky, mind-fogged symptoms of mild hypoglycemia when your blood sugar and insulin levels are perfectly normal.

(The most important difference between "real" diabetic hypoglycemia and this pseudo-hypoglycemia is that the second version isn't dangerous. Just have a lie down, and in due course your body will drift back into homeostasis and you'll feel better. If a diabetic tries treating hypoglycemia that way, they can end up very ill, or dead.)

A transient hypoglycemic state does feel like a post-stimulant "crash", so there's solid basic biology behind that half of the "sugar rush" experience. There just isn't any actual rush at the start, unless you were hungry enough to feel faint when you ate that block of chocolate or drank that Humongous Gulp of fizzy sugar-water. And in that case, you again didn't get an actual rush, just a rapid return to normal function, which under the circumstances you could easily interpret as a rush.

(I'm ignoring, for the purposes of this discussion, the case of caffeinated drinks. Those certainly can give you some sort of "rush", followed by a crash, but it's not because of the sugar.)

So why do so many people swear that their kids go hyperactive when full of ultra-high-glycemic-index party food?

Well, it's partly because small children at birthday parties have a tendency to go nuts no matter what you feed them. And it's partly a placebo effect.

It doesn't seem as if it should be a placebo, though. If a child's had it drummed into them that they're expected to go hyperactive when they eat lollies, it wouldn't be terribly surprising if they did. But without such an expectation, sugar should have no particular placebo effect on the child.

But the placebo effect we're talking about here isn't happening to the child. It's happening to the adults who're observing the child. I don't know if there's been much research into this, but it's plausible for a couple of reasons. One is this study, which found that mothers who believed their young sons were "sugar sensitive" were more likely to perceive hyperactivity in their child if they're told the boy had been fed sugar, and less likely if they believed the boy had had an artificial sweetener, even though all of the children in the study actually got the artificial sweetener.

The second reason is that an analogous situation exists in veterinary medicine.

There are all sorts of nutty woo-woo alternative-medicine treatments available for animals, even openly preposterous activities like chiropractic adjustments for horses, performed by human beings with their bare hands. To actually shift the vertebrae of a horse around you'd need the assistance of the Incredible Hulk, or at least a very large mallet. But there the horse-chiros are, prodding and pushing and pretending something's moving (see also, "craniosacral therapy"...), and it's not hard to find horse owners who're convinced their animal's much healthier after the pantomime is complete.

So this is the placebo effect at one remove. The owner of the horse, or the parent of the child, can swear up and down that they see a clear difference, when one does not in fact exist.

(There can also be a direct placebo effect in veterinary medicine; an animal can be expected to change its behaviour if a strange person comes and messes with it, whether or not anything of real medical value is taking place. Animals are renowned for perking up when you take them to the vet, the usual explanation given being that they're in a scary environment and trying to look as strong and healthy as possible to avoid being selected for lunch by some unseen predator. This is a bit of a Just-So Story, though, because there's no way to prove it right or wrong until someone finds a talking dog. But never mind that for now.)

There are good reasons not to feed your kids a lot of sugar. But there's no reason to suppose, and several reasons to not suppose, that sugar has anything to do with hyperactivity.

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.

A reader writes:

Hey, I get cheese sweats too!

While we're on the subject, when I drink alcohol, especially spirits, it makes me feel warm, starting in the stomach and moving out. How "real" is this effect? I presume it's not actually changing my core body temperature, because that'd make a shot of Jack Daniels a life-threatening event. What's actually going on?

Derrick

Alcohol indeed does not change your core temperature, but it genuinely can change the distribution of heat in your body. Ethanol is a vasodilator; it causes the smooth muscle around blood vessels to relax and let more blood through. If the ambient temperature is cool, your peripheral blood vessels will naturally be somewhat constricted, reducing blood flow to your extremities; when the vessels dilate, more warm blood flows through those outer vessels, the tissue there thus warms up, and you feel warmer. Because some parts of you genuinely are.

In extreme situations, this can be dangerous. The reason why the body constricts outer blood vessels when it's cold is specifically to avoid losing valuable heat via the extremities. Knock back some Scotch when you're hypothermic and it'll make you feel better (because of both the vasodilatory warming effect, and the psychoactive effects of the alcohol), but you'll also accelerate heat loss and actually make the situation worse.

(For this reason, although St. Bernards are used for alpine rescue, they've never had little barrels of brandy hanging around their necks. Oh, and the whole vasodilator thing also made the traditional use of alcohol as a snake-bite remedy actually a really bad idea.)

In non-life-threatening situations, like when you're cold but not dangerously so and come in to sit by the fire in the ski lodge, alcohol may help you warm up by increasing blood flow through the extremities that're now being warmed by the fire. More prosaically, an alcoholic nightcap can help with that vicious circle where you get into bed with cold feet and your feet stay cold, because cold feet don't have the blood flow to produce much heat for the bedclothes to retain.

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.

A reader writes:

When I eat cheese, I sweat. I don't really feel hot, I just break out in a sweat.

Sweating when you eat a curry, that I understand. Or a big hot dinner; that could actually physically heat you up. But cheese? WTF?

Don

There's a compound in aged cheese, tyramine, that induces the release of epinephrine (a.k.a. adrenaline), and some related neurotransmitters. The result is a sort of mini-fight-or-flight reaction, including a faster heartbeat and, as you say, sweating.

Tyramine affects different people differently; many people don't notice the effect at all. I think the effect can vary from day to day and depending on how much cheese you've eaten. It does for me, anyway; sometimes vintage cheddar gives me a cheese-sweat, sometimes it doesn't.

Speaking of which, the type of cheese definitely matters. Un-aged cheeses, like cream cheese or cottage cheese or Kraft Reprocessed 580-Nanometer Partially Homologated Polymer Dairy Analogue, contain very little tyramine. As a general rule, the stronger-flavoured the cheese, the more tyramine there'll be.

It's the tyramine, by the way, that makes it a bad idea to consume vintage cheese if you're also taking a monoamine oxidase inhibitor drug. Old-style "irreversible" MAOIs plot to kill you in a few different ways, one of which is giving you a massive blood-pressure spike if, in cheerful defiance of the common sense of more than half of the world's population, you eat something which used to be milk, but has been left to sit for years on end and is now a stinking mould-covered lump of obviously lethal putrescence.

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.

A reader writes:

What's the chemical difference between soap and detergent? I know soap's made by reacting an oily substance and an alkali; is detergent made some other way?

Jun

Soap is, as you say, a class of substances with a clear chemical definition; a soap is a salt of a fatty acid. Soap molecules, in brief, are hydrophilic on one end and lipophilic on the other, and so allow oils to disperse in water.

Detergents are less clearly defined. One old definition of "detergent" says it's just any substance you use to clean something. By that definition, plain water is the most common detergent, and soap is detergent too. Sand counts as a detergent by this definition, because you can scour pots with it.

The standard home-and-garden definition of a detergent is, of course, much more limited; it covers dishwashing liquid, dishwasher powder, laundry liquid and powder, and so on. Any consumable cleaning substance that doesn't come in a solid bar, or in a pump-pack with "Soap" written on it somewhere.

These detergents contain one or more surfactants that do something similar to what soap does - often the ubiquitous sodium lauryl and/or laureth sulfate, which are not actually incredibly good at cleaning, but are very good at making the rich bubbly lather that consumers have been trained to equate with cleaning power. On top of that, there's "builders" that make the surfactant work better, and various other substances suited to the application. Oh, and in the case of liquid detergents, there's also quite a lot of water, which I've heard referred to by a formulator of shampoo and conditioner as "profitrol".

There are lots of substances that, like plain water, can fill the role of a detergent without containing surfactants. Sodium carbonate or bicarbonate, for instance, can be used as a fairly effective remover of oily substances all by themselves, essentially because they're alkaline and make a little of their own soap from whatever oils are on the thing to be cleaned. Sodium carbonate and bicarbonate are, however, not alkaline enough to be dangerous (unlike the standard soap-making alkali, sodium hydroxide), and also quite non-toxic, so you can use them straight as dishwasher powder with decent results if you're out of the detergent-y stuff.

(Note that some non-standard cleaning products actually have little or no effect at all. The classic example is the magical plastic laundry ball, which doesn't actually do anything, but may appear to work without any other detergent because plain detergent-less water will clean your clothes to some extent all by itself. See also, stone soup.)

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.