Hi Piers:-)
Nice work Watson. But if one gains most of their heat in a cold environment
from the digestion of prey, camouflage allows you to get closer to your
prey, so not to be ruled out lightly. If the white thing was that
temperature driven, where were the seals when they gave the thermal color
class? Penguins must have skipped some classes (more black than white) and
as your point out yourself, my dear Watson, "A light coloured bag will
provide better heat insulation (keeping heat in, as well as keeping heat
out) than a dark bag." So if I was a polar bear I'd want to absorb heat and
be dark, but I'd want to eat so I would want to look like the surroundings
so I'd be white, the dilemma is angering, which may explain their
temperment. Should you choose to research this further, you should know what
Polar Bears call photographers--- "food"!
As for the color of a bag, the thermal properties of material and thickness
would have greater effect than exterior color, all of which become fairly
irrelavent the longer the exposure, (40 below gets in your bag sooner or
later), and there is the rude fact that if you are going to use your camera
you have to take it out of the bag. I'd leave you with that deduction
Watson and I'd like to thank Gord for the use of his computer.
Sherlock
----- Original Message -----
From: "Piers Hemy" <piers@xxxxxxxx>
To: <olympus@xxxxxxxxxx>
Sent: Monday, February 02, 2004 5:37 AM
Subject: [OM] Re: Camera Bags
>
> OK, I need to regain some respect from Fred Winterbottom (see earlier
> posts!)...
>
> You're both right and wrong.
>
> Darker coloured bodies transmit heat more effectively than lighter
coloured
> bodies.
>
> So if your bag contents are warmer than the surroundings, they will cool -
> by radiating their relative heat - quicker in a dark bag than in a light
bag
> (and heat up quicker if they are colder than the surroundings). A light
> coloured bag will provide better heat insulation (keeping heat in, as well
> as keeping heat out) than a dark bag.
>
> Perhaps this explains why polar bears are white not black - it's unlikely
to
> be for camouflage, after all, since there's no predator to spot them, and
> the prey are under the ice, so it must be because they keep warmer that
way!
> From which we can deduce that there is less heat to be absorbed from the
sun
> up there than can be generated from digestion of seals.
>
> Piers
>
>
> -----Original Message-----
> From: olympus-owner@xxxxxxxxxx [mailto:olympus-owner@xxxxxxxxxx] On Behalf
> Of Chris Barker
> Sent: 02 February 2004 12:09
> To: olympus@xxxxxxxxxx
> Subject: [OM] Re: Camera Bags
>
>
> -- snip
> Furthermore, I don't think that a darker colour actually "radiates" heat.
> All it does is absorb more heat if there is heat to be absorbed.
>
> -- snip
>
> Chris
>
> On 2 Feb 2004 , at 10:20, CyberSimian wrote:
>
> -- snip
>
> > At the other extreme, since a black surface radiates heat more quickly
> > than any other colour, a black bag in subzero temperatures will cool
> > the contents as rapidly as possible (not the best environment for
> > silver oxide batteries!). A white bag would delay the cooling for as
> > long as possible.
>
> -- snip
>
>
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