Month: January 2008

Was rather confused when I read this article about a mono-monostatic object – an object that can right itself to a single equilibrium position no matter its starting position – discovered by Hungarian mathematicians.

Watching a demonstration on their website, it struck me that I’d seen something a little bit like this – and suddenly remembered a little song we used to sing in Primary School about righting yourself after you fall, just like a ä¸å€’翁.

If you can’t read Chinese, Wikipedia’s English Page describes it as a “Daruma Doll“, a self-righting doll. It’s been around in China more than a millenium, though it appears not to have penetrated into the West.

So now I’m a little confused as to what the big fuss about the Gomboc is. Unless homogenous Daruma Dolls can’t right themselves (which in my mind seems entirely likely), the Gomboc just seems like that US multi-million-dollar-pen project (vs the Russian pencil). But if so, then the last paragraph of the NYT article doesn’t make much sense:

Yet the scientists now say that Mother Nature may have beaten them in the race after all. They have noticed that the Gomboc closely resembles the shell of a tortoise or a beetle, creatures whose round-shelled backs help them right themselves when flipped over. “We discovered it with mathematics,” Domokos notes, “but evolution got there first.”

Because we know that turtles definitely aren’t homogenous. They contain intestines and stuff.

Anyone any wiser?

Update: turns out that the traditional Chinese toy, in fact, is only able to right itself because it is not made of a uniform material (usually hollow or weighted). The Gomboc, on the other hand, is a mathematical marvel because it is of a uniform material and thus will work with any material. This article on sina.com explains all (but is unfortunately in Chinese) and also points out that the Hungarians know how to have fun with Maths – they invented the Rubik’s cube too.

Intuition begone!

Watched an episode of QI where Sean Lock mentions that Banana plants “walk” (about 2:14 in the clip below). Steven Fry confirms it a little later, according to a “little voice in his head”.

(aside: I’m beginning to think it was scripted, because I found the transcript of an interview he gave for the Science Show where he says something about reading about Malayan dendrology and walking banana plants, so Steven must have known about the moving plants–but perhaps they thought people would believe Sean more)

It’s been haunting me ever since, because I simply cannot imagine how a plant can walk. There’s the issue of roots which make walking tautologically impossible, aren’t they?

So of course being the internet-savvy-type that I am, I queried Wikipedia, and got this:

… the individual stools or planting sites may move slightly from their original positions as lateral rhizome formation dictates. Latin Americans sometimes comment that the plants are “walking” over time.

Aha! I proudly thought – so banana trees DO walk! I MUST tell absolutely everyone I know!

I’m not sure why the question came back to haunt me today, but it did, and I puzzled over the long cab ride home why no one had ever taken a capture of a banana tree walking. Surely a horizontally moving plant would be YouTube fodder or at least of some interest to the Discovery Channel?

So I did a bit more research and now I’m ready to kick myself in the ass, because I’d actually been given all the information I needed to connect the dots, but didn’t. There doesn’t seem to be a ready internet answer to this, so in apology to the people I may have given erroneous information to, here’s an attempt at a reconciliation of the facts.

My basic assumption in thinking that “banana trees can walk” was entirely false – the fact that bananas are trees at all. They aren’t. Bananas are herbs. What that means is that the thing you see sticking out of the ground with the leaves and fruit (the pseudostem) only comprises a part of the banana tree. The actual stem of the banana tree (the corm) is underground (think of ginger).

The pseudostem “matures” in 6 – 8 months, producing fruit and then dying. Usually, another smaller pseudostem will have simultaneously started growing at the same base of the original pseudostem, which will then take over the job of photosynthesis and any other pseudostem roles and responsibilities. The new pseudostem will be, of course, slightly displaced from the position of the old one (see image). Because a banana plant can be cultivated for 25 years and the pseudostems have a relatively short lifespan, as pseudostems die and get replaced it can look as though the plant has “walked” whereas in fact it is the change in position of pseudostems as they replace each other. The only thing that has really “walked” is the position at which the banana corm grows its pseudostem.

In fact I should know this from experience, because I’ve tried to cut down a banana plant and remove its roots (as I thought then) before, and do remember thinking to myself that they extended a bloody long distance and were ridiculously thick. I guess being in a jungle sweating it out with a parang and spade don’t incline you towards pondering the oddness of Nature.

So there you have it. Banana plants don’t walk, not in the slightest. The illusion that they “walk” is due to the withering and resprouting of pseudostems from the underground stem. I’ve learnt something new today (thanks to QI) and I hope you have too. Now go forth, and spread your newly-found wisdom!

But do remember to make use of the air quotes.