Reflecting cold

[Newshound]

Read it again

[Roger Chapman]

My money would be on the figures being quoted the wrong way round. (Not that I am prepared to bet on anything less than a dead cert so no money is offered).

[Terry Fields]

Doh!

Yes, you're quite right, sorry about that - I'm banging down painkillers to deal with a grumbling appendix, and don't have a great attention span ATM. Apologies to all.

Terry Fields

[Ian Jackson]

In message , "dennis@home" writes

And that light bulbs work by sucking the darkness in.

[Brian Gaff]

Surely what you need is a heat pip behind it attached to a large black lump of something then you can just stick a radiator on the other end and slavage the lost heat... Well its as scientific as the thread title!

Brian

[Gib Bogle]

url:

> Reflecting cold? That's an interesting concept.

If heat is infra-red EM radiation, what is cold, I wonder?

[Gib Bogle]

In this case feeling cold is more related to the conducting properties of the glass. If instead of glass you had a sheet of steel it would feel just as cold, since what you are feeling is basically the temperature outside. In both cases the temperature drop across the sheet is quite small. The temperature in the room is determined by (among other things) the sum of the amount of radiant heat going out the window and the amount of heat conduction through the window. With steel instead of glass the conduction would be more, but the radiant loss would be zero. It's not clear (to me) without doing some calculations which would make the room warmer, but I suspect that the conduction loss dominates.

[Gib Bogle]

url:

>>>>> Reflecting cold? That's an interesting concept.

In any case more heat is lost from the body by conduction-convection than by radiation, I believe. Evaporative cooling (sweat) can also be very significant.

[Gib Bogle]

Sounds about right, and consistent with the MBS.

[robgraham]

Cold is the absorption of heat isn't it - it's a heat sink.

The first winters in this cottage were pretty miserable - just as well we were young. Possibly late 18th century build with 3 ft thick stone walls, it was probably warmer when built than when it was upgraded in the late 1920's to have a proper wooden floor and lathe and plaster on the walls, but they didn't put two and two together that all the under floor ventilating air just circulated up behind the L and P and out through the rood space, so the room insulation was just 2cm of plaster, above and all round; the basic coal fire would radiantly heat your front and the walls just seemed to suck all your warmth away from your back.

Rob

[Davey]

I think it's time to resurrect the Phlogiston theory.

[Frank Erskine]

And miasma/contagion :-)

Actually the idea of hot/cold isn't too silly.

In the morning I open the living-room curtains to let the darkness out, which is just the reverse logic to letting the light in.

It's all relative/relativity really innit...

[Frank Erskine]

ITYF it's "lath and plaster". A lathe is a machine for turning e.g. wood or metal..

HTH

[The Natural Philosopher]

*shrug* Its a theory. But really, what isn't?

(serious deep question)

[The Natural Philosopher]

url:

A virus

[PeterC]

An expectorant will help to get rid of that.

[dennis]

The idea that the mass of an object changes depending on how much energy it has isn't according to you.

[Davey]

Relatively speaking, yes it is.

So how do we deal with those people who annoyingly describe something as being 'three times smaller' than something else?

[The Natural Philosopher]

Well that's what the theory of relativity says... and the instruments say..

[The Natural Philosopher]

harrys, Drivels or dennisses?