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  • Hit or miss: fun on the mountain bike

    Mountain biking (an all to rare occurrence for me these days) is not a purely physical exercise; the brain is given a real workout, too. I’ll concede straight away that it’s by no means an intellectual exercise - I’m not necessarily thinking of anything at all (also a rare occurrence, one to be encouraged). But sometimes I become aware of the sheer mass of calculations that the brain is performing whilst I’m on the bike. It’s thinking almost as hard as the legs are pumping.

    Of the many types of calculations buzzing around in my head, the most satisfying for me is the “hit or miss” question. I’m pedalling along a trail, at best upwards, and there’s a rock in the way. Now, I can miss the rock with my wheels simply by steering away from it. But if things are tight and there isn’t much room for manoeuvre, I start wondering if I’m going to bottom out with my pedals - which is usually a worse situation than hitting a rock with the wheel.

    Is that pedal going to hit that rock (and who's going to come of worse?)

     Pedals don't have big fat tyres or squishy suspension. What they feel, you feel.

    With the pedals entering a zone of uncertainty, the brain embarks upon a series of vector-style calculations, that goes something like this:

    - my current gearing (including wheel size) is such that
    - if I keep pedalling at the same rate
    - from this current rotational position
    - and with my pedals at this height from the ground, I will
    - miss / just miss / hit that rock

    If I am going to grind the pedal on that rock, with all the ensuing discomforts, I can take action with a few more calculations:
    - at this vertical incline I have sufficient momentum to be able to stop pedalling briefly without completely losing forward motion
    - I can change gear to change the rate of rotation of the pedal in question
    - I can incline the bike to one side, raising the pedal height
    - I can attempt to raise the height of the whole bike (by trying something silly like a bunny-hop)
    - I will need to ride over the rock (thereby starting a new set of calculations)

    But by far the most satisfying result of all of this is the near miss. It's a confirmation that everything the brain worked out was correct, and that gives it an immense sense of pride - whatever that means in brain-speak (hormones, of course).

    So, whenever you're next out on your bike, even if you're out and about in town rather than downhilling, just be aware of and amazed at all the things you don't hit.
    → 11:09 PM, Nov 24
  • Figuring auf Deutsch

    Arithmetic, from University Department of Computer Science


    Years ago, Dad bought a lovely little book called Figuring, by the arithmetical genius Shakuntala Devi.

    It's a book on the joys of numbers. According to the rather short Wikipedia article on her:

    "On June 18, 1980 she demonstrated the multiplication of two 13-digit numbers 7,686,369,774,870 x 2,465,099,745,779 picked at random by the Computer Department of Imperial College, London. She answered the question in 28 seconds. However, this time is more likely the time for dictating the answer (a 26-digit number) than the time for the mental calculation (the time of 28 seconds was quoted on her own website). Her correct answer was 18,947,668,177,995,426,462,773,730. This event is mentioned on page 26 of the 1995 Guinness Book of Records"

    I am of course light years away from such talents, but I was never really terrible at it. However, I notice more and more that I have given up on trying to work out multiplications in my head. It's not that I have become mentally lazy - well, I have, but it's not in the way that you might think.

    The problem is German numbers. They are so backwards and incoherently wrong that I have simply given up on trying to work with them.

    683 is spoken in German six hundred three and eighty. The hundreds number, 8 is easily buffered in my memory. However, I have to hold the final three in my head until I hear the tens "eight" before I can actually do anything with the number. In English, I can directly translate "six hundred and eighty-three" into 6-8-3. This has so confused me over the years that I have swallowed my pride and reach for the calculator as soon as I can.
    → 8:47 PM, Jul 11
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