["Followup-To:" header set to talk.origins.]
On 2006-06-23, don findlay wrote:
Debunking Plate Tectonics - Strike 2.

Concerning soup, porridge and tea
(and simpletons like me...)

Since Robert Grumbine recommended beating some cornstarch with a spoon
to appreciate what mantle flow as a viscous solid was all about, I
thought I'd make a pot of tea to see what convection was all about as a
fluid.

Now the interesting thing here is that it tumbles nineteen to the dozen
down below, but the skin on the top is is as solid as a rock. How
come? What's more if you stir it with a spoon then you get all this
wild whirling dervish inside the tea, but after a minute the skin sits
still while underneath the surface it keeps whirling.

What's even more is, if you let it cool down, then put it back on the
heat to heat it up again, very soon you begin to get a bit of steam,
and the skin starts to form (again), (somehow it wasn't there to begin
with the second time), this time with the odd tea leaf embedded in it.
The skin is a surface of heat exchange between what's going on down
below (the leaves are again going helter skelter up and down , more or
less in place) and what's going on up above (steam). And gradually tea
leaves get caught in this skin, where they stay (again) solid as a
rock. When it gets really stewed you could just about stand on the
stuff its so solid with clotted tea leaves. That are not moving at
all, even though everything down below is. Like crazy.

And my porridge goes 'plop' and hits me me in the eye when I put it on
the heat.

And so does my soup.

Nothing to do with skin convects at all .

And when I look at those nice pics of convection on the web, they're
all numerical simulations. Tweaked to look good.

So what bit of this 'convection' model am I supposed to swallow?

Oh dear. When you suffer a head injury, you really should go to
the hospital and have them check to see that the trauma isn't this
serious.

Mark