 Poster: A snowHead
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| ecureuil wrote: |
| doddsie wrote: |
| ... I can't do much more to keep the body warmer, yesterday I had 6 layers on my body and 3 layers on my legs, all high quality stuff and still got too cold to ski in the afternoon at -5c. |
How many on your head? As others have said, extremities get cold because the body reduces circulation to those areas in order to protect the core temperature. Heat loss is generally proportional to the amount of exposed skin (leading to the "50% of heat lost from your head" rule in mountain environments when the rest of your body is relatively well insulated). Consider buffs, neckwarmers, balaclavas, etc. |
Good points, but you do know the 50% heat lost from your head is a myth ...
https://www.theguardian.com/science/2008/dec/17/medicalresearch-humanbehaviour
Edit: ahh, now I re-read, I see you do 
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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| snowdave wrote: |
| @CEM, it might serve to conduct heat from a warm part of the foot to a cold part thus make e.g. the toes feel warmer at the cost of a colder heel or midfoot. However, as an insulator I can’t see it doing anything - taken to an extreme, would a metal insole be warmer or colder than a plastic one? |
It reflects cold back out the boot and may heat towards the foot
If it didn’t work why would footbed manufacturers bother putting foil on me bottom of some of their footbeds, when I have time ( be a few weeks) I will find the data from the footbed companies
Beyond that you can believe what you like, having had a foil layer in my race boots for s few years I can happily say it made a difference
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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Ecureuil - On sunday I got too cold with 2 layers on my head, a thermal balaclava and a thick woolly hat. Thinking about it, I can't remember a single day skiing this season when I haven't been cold, so I think I may have to buy a whole new wardrobe this summer, before next season. Only this weekend to get through and then 2 weeks at Easter when I'm hoping it'll be warm enough to sunbathe in the afternoons like the last couple of years.
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You need to Login to know who's really who.
You need to Login to know who's really who.
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@CEM, we can all believe what we like, but in some cases physics disagrees with us. You can't reflect cold because cold is simply the absence of heat.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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You'll need to Register first of course.
You'll need to Register first of course.
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Emiting less isn’t the same as reflecting cold tho. Broadly, radiated heat behaves like light, and cold is like dark. You can’t reflect dark, you can’t make dark, all you can do is block light. A mirror doesn’t reflect darkness, it just reflects no light if you angle it at a dark areal, you can’t reflect darkness to make something darker, you can just ensure that an area of space provides no light.
In the case of foil insoles, this is very similar. Foil reduces emissivity, but the part of the ski boot that is emitting the vast majority of infra red is the top, so wrapping the top of your ski boot in foil might actually help. If the sole of your boot is emitting IR, then putting foil in the middle inside won’t help. Putting it on the outside of the sole would help, but nobody does that because radiative heat loss isn’t an issue, it’s conductive loss to the ski, the air and the snow that’s the problem.
Your feet aren’t radiating heat into your ski boot, they are conducting it. Your ski boot might then radiate heat to free space, but to block radiative heat loss you’d need the foil at the interface where the radiation occurs, ie the outside.
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@snowdave, as soon as there is any sort of air gap between the two surfaces then radiant heat will come into play. So, unless you are going to suck out all the air in your boots, it will have an effect.
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FAQ
