Egg timers

On several occasions now, while brushing my teeth to one or other of my egg timers (see, for example, reference 1), I have focused on the grains of sand. Sometimes it is so clear that I want to count the grains, perhaps a throw back to the days when I did maths. I then get to wondering about how one would compute the behaviour of the grains of sand as they went through the neck of the timer. On the one hand there are rather a lot of grains to compute at once, on the other their micro behaviour is going to be dependent on the shapes and positions of the grains just above the neck. Can one do better than just plotting the presumably narrow bell curve one gets if one times lots of eggs? And then there is the question of how do you make the things? Do you have to leave a hole at one end so that you can adjust the sand content or what?

Then yesterday, while browsing in the work of the Fingelkurts twins, Andrew and Alexander, I stumble across the study of self-ordered criticality, something with which I cannot claim any familiarity whatsoever, although it is possible that that may change. In the meantime, it seems that one branch of this study is concerned with avalanches, so concerned for the central example of the intermittent small avalanches that one gets around the cone of the growing pile of sand in the bottom half of an egg timer. I think the idea is that just before the avalanche the sand is in one critical state, and just after, another. Or perhaps an unstable equilibrium. So not quite the problem that caught my attention, but warm enough.

The Fingelkurts twins are an interesting pair, born in Russia, but who have set up shop in Finland. I wonder if they number among what I imagine is the small number of foreigners who bother to learn Finnish? I also wonder about how they get on with the locals, considering the history between the two places. See reference 2, from which I have taken the illustration of their interesting CV, interesting that is for a pair who wound up in neurology. Don't suppose anyone nearer home can match it.

Reference 1: http://psmv2.blogspot.co.uk/2015/06/older-teeth.html.

Reference 2: http://www.bm-science.com/.