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09
Nov 2001
Wilson A Bentley: Public Domain Photo
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Under
the microscope, I found that snowflakes were miracles of beauty, and
it seemed a shame that this beauty should not be seen and appreciated
by others. Every crystal was a masterpiece of design and
no one design was ever repeated. When a snowflake melted,
that design was forever lost. Just that much beauty was
gone, without leaving any record behind.
Wilson "Snowflake" Bentley: 1925
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Snowflakes
This belief (that no two snowflakes are ever the same) dates quite
specifically back to Wilson Bentley and the 5000 snowflakes he
photographed. There are indeed millions of patterns, but scientists
point out that the supposed uniqueness of each snowflake is not so:
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Research
scientist Ken Fuller concentrates his attack on the statistical
implications, pointing out that 5000 snowflakes will not even
make a snowball, let alone account for the earth's total production
of snow over the last 500m years. He also claims that
Bentley concentrated on the more striking stellar snowflakes,
ignoring columnar, needle and plate crystals.
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John
Bechhoefer of Chicago University says that the shape of a snowflake
depends on the temperature at the interface between ice and
water vapour, and on the relative humidity at that temperature,
and "if two snowflakes are grown under identical conditions
they will appear almost identical". He then adds
the caveat that in practice each falling snowflake encounters
a unique set of conditions.
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Pao-Kaun
Wang, an atmospheric physicist at Wisconsin, is quite laid-back
about it: "Going down to the molecular level, of course
they're all different", he says, "but without a microscope,
they may look alike".
Structure
at the molecular level being immaterial (you might as well claim
that no two ball-bearings are the same) it seems that this is one
story which is much exaggerated.
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Plugholes
Don't believe everything you see on The Simpsons:
water does not swirl away anti-clockwise in the Northern hemisphere,
and clockwise in the Southern hemisphere. The Coriolis
effect, caused by the Earth's rotation, does influence hurricanes
and other meteorological phenomena, but that is only because the (very
weak) effect has time to work on large-scale, long-lasting systems;
it has no effect at all in normal domestic conditions. Yes,
successful experiments can be set up on a smaller scale, but they
have to be done in laboratory conditions - typically with the water
being left undisturbed for at least a week - and using specially-designed
tanks.
On Pole To Pole, Michael
Palin was taken in by a hustler in Kenya, who made money "demonstrating"
the Coriolis effect to tourists on one side of the equator, then
moving a few yards south and performing his trick on (supposedly)
the other side of the equator. The best of luck to the guy,
I say. The suckers tourists will have a lot
more money than he has, so why not take a few of them with a harmless
little scam?
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Head
Lice
Have you never been suspicious of the tale that head lice prefer
clean hair? It's all too reassuring, too convenient, too good
to be true. It just smells of some propaganda put about so as
not to discourage people from reporting infestation - and you can
hardly deny it must be some comfort for people to say, "The kids
have got lice, but they only happen in the cleanest of households,
you know". Anyway, here's Ian Burgess, of the Medical
Entomology Centre near Cambridge. Burgess has been working with
lice for 28 years, and knows a bit about his subject:
That was invented
to convince middle-class parents that their children too could
catch lice. At the time people believed that lice
were found only on dirty slum-dwellers. Of course it isn't
true. They couldn't give two tuppenny damns. As long
as there is blood underneath it, they will feed there.
The bad news about this for
kids is they've just lost their excuse for not keeping clean.
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Dark
Side Of The Moon
There is no permanently dark side of the Moon. Seen from the
surface of the earth the Moon does not appear to rotate. The
Moon rotates once every time it goes round the Earth, and it is always
the same side that presents itself to us. So there is a far
side of the Moon that no-one on Earth ever sees; but that side
is illuminated at different times by the Sun, and is not permanently
dark. |
The
Black Death
Ring a Ring of Roses is the subject of one of the most notorious
myths of the last few decades, namely that the rhyme originated either
in the Great Plague of London (1664-1666) or in the Black Death of
the 14th century. The story was even regurgitated uncritically
on a recent BBC programme about The Great Plague. The
truth is that Ring a Ring of Roses is first recorded in print
in 1881, and then only as one variant of a family of similar rhymes.
Folklorists have been collecting and recording oral tradition for
centuries; is it all likely - especially considering an origin
of such significance - that a children's game should first have been
recorded 200 years, perhaps even 500 years, after its invention?
The leading authorities (Peter
& Iona Opie, editors of The Oxford Dictionary of Nursery
Rhymes) see no reason at all to link Ring a Ring of Roses
with Bubonic Plague, and are dismissive about the idea. As
to what the real origin is, the folklorist Philip Hiscock makes
a plausible case that the rhyme originated in 19th century teenagers'
games designed to get round puritanical bans on dancing in some
households. Actually, no-one committed the idea to print until
1961, when James Leasor published The Plague and The Fire,
so it's not even as if there is any long tradition of the link with
Bubonic Plague.
You can't say never, and you
can't say there is definitely no link; what you can say is
that there is no evidence at all for the theory apart from pure
imagination, and there are many good reasons for rejecting the idea.
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Ernst
Haeckel's Embryos
The more I read about this, the more confused I get. Are there
any embryologists out there? |
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