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White out v Flat light (physics)

 Poster: A snowHead
Poster: A snowHead
Wayne wrote:
abc wrote:
The finer consideration of physics: flat light concern more about the source of light, while white out is due to reflected light unable to reach the eye.

Hmmmm, not really, as this would suppose that a white out is perceptual (visual illusion), but it's not. Even if there is no eye there to receive the light, the condition would still exist.

Aren't we straying away from physics into philosophy?

If there's no eyes, all that talk about disorientation doesn't have any bearing at all.

Richard_Sideways wrote:
Well, if we are doing pictures, have a repost of the best flatlight example i've ever seen.
http://upload.wikimedia.org/wikipedia/commons/thumb/3/37/White-out_hg.jpg/640px-White-out_hg.jpg

That's a good one. I had something similar in my head too!
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 Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
Hmmm. OK then, multiple thread drifts here we come Laughing

altis wrote:
A picture is worth a thousand words:

Not in this case wink
The picture displays a "possible" result without any explanation of causation, or even what the picture is a reference to. Also, when used in the context of this thread, it’s inaccurate.
Graphics are useful in demonstrating a section of a process, display a sequence, etc. But they very rarely adequately take the place of explanation


abc wrote:
Aren't we straying away from physics into philosophy?
If there's no eyes, all that talk about disorientation doesn't have any bearing at all.


Disorientation is a possible physical result of someone experiencing the condition, it is not a property of the condition.
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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?
Wayne wrote:
Hmmm. OK then, multiple thread drifts here we come Laughing

altis wrote:
A picture is worth a thousand words:

Not in this case wink
The picture displays a "possible" result without any explanation of causation, or even what the picture is a reference to. Also, when used in the context of this thread, it’s inaccurate.

I happen to think that picture is pretty good.

What do you see as inaccurate about the picture?
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You need to Login to know who's really who.
This is actually quite interesting (in a dull sciency way) You've got multiple affects happening to the light - transitioning through the same material in different states.

Quote:
Disorientation is a possible physical result of someone experiencing the condition, it is not a property of the condition.

Spoken like a true scientist, possibly one with the blood of several co-workers on his labcoat and ALL OVER the new highspeed centrifuge... Madeye-Smiley
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 Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
Quote:

I happen to think that picture is pretty good

I think it's pretty good, too, if it's genuine - you can see detail of figures in the distance, perfectly well, but no detail at all down on the snow. It's a bit weird though, in an attractive sort of way.
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You'll need to Register first of course.
abc wrote:
Wayne wrote:
Hmmm. OK then, multiple thread drifts here we come Laughing

altis wrote:
A picture is worth a thousand words:

Not in this case wink
The picture displays a "possible" result without any explanation of causation, or even what the picture is a reference to. Also, when used in the context of this thread, it’s inaccurate.

I happen to think that picture is pretty good.

Spot on. IMV, if you take issue with the picture, you might still be misunderstanding the two phenomena. Of course, by simplifying things, it can't describe all scenarios, such as the flat light that occurs at twightlight or when you move into deep shade.

The picture also explains why amber goggles help to improve visibility in flat light. Yellow light is less susceptible to scattering than higher frequencies, so, by filtering out the blue spectrum, you're also reducing the proportion of scattered light entering the eye and reducing the impact of the white-out. However, amber goggles don't work in a white-out casued by shade or twilight, because, in those scenarios, everything you see is illuminated by scattered light.
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 Then you can post your own questions or snow reports...
Then you can post your own questions or snow reports...
Hangon, Hang on, I was refering to the graphic
this one



NOT the photo - which I think is quite good
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 After all it is free Go on u know u want to!
After all it is free Go on u know u want to!
Jonny Jones wrote:
Yellow light is less susceptible to scattering than higher frequencies, so, by filtering out the blue spectrum, you're also reducing the proportion of scattered light entering the eye and reducing the impact of the white-out.


Puzzled WHAT Puzzled

"Any" wavelength will be scattered by the same proportion if the reflector is equal to ....
no no no no I must stop Very Happy Toofy Grin Smile Madeye-Smiley

It's tea time

aaaaarrrrrrrrggggggghhhhhhhhh


I am going to write out a thousand times.
I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer. I must not answer.

Well maybe not 1,000, but lots anyway Laughing
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I always assumed that white out = in the cloud, and flat light = under the cloud. Flat light is when there is effectively a diffuse light source rather than a point source so it doesn't create shadows very well and this makes it harder to pick things out.

(I accept I may be totally wrong)
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Quick! While he's gone lets make up some science!

Wayne wrote:
Water has a 4th state called 'nonchalent' that only happens when it's in the presence of smooth Jazz Cool

Wayne wrote:
The sphere was discovered by the father of modern science, Johnny Ball, hence the name.
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Richard_Sideways wrote:
Quick! While he's gone lets make up some science!


Well then I’m back on the main section of the paper (the white/flat stuff was just one of the footnote).

BUT

My calculator say that’s snow is invisible.

Truly.

Think about it like this.

Q. Why can you see anything that is in itself not a light source?
A. Because you see the light that it is reflecting. And the light is reflected in a way that is defined by the object you’re looking. eg it is dark, light, red, blue, a tiger, a cup of tea, admin on skis, etc.

OK up to now?

Next the standard stuff (that’s I’m putting into my calculator) says this. The angle of reflection equals the angle of incidence. Geek talk for something reflects at the same angle that it hits. So if you look into a mirror at say 25’ you will be able to see (assuming it’s a good and VERY small mirror) stuff that is at 25’ on the other side.

Still OK.

BUT, snow is made of crystals (bare with me on this one) and crystals have facets (geek talk for sides and top and bottom) and each facet is (due to stupid way in which ice crystal grow in the atmosphere) fractalised – that is it gets smaller and smaller each time it grows and it grows in a set way – arrrrhhhh, that why snowflake look so pretty.

Anyway, assuming that the facets are fractalised and the lowest fractal (which it must be as ice isn't solid all the way to the top - there is always a bit of water in the QLL) is a single H2O molecule, which is less than 300nm (in reality it’s around 276 to 280) but anyway the smallest wavelength we (people) can distinguish is around 380nm (at the blue/violet end of the colour thing).


QED all snow must be invisible as it's not possible for light to reflect off it in a wavelength that we can see.

Sod it, I’m off to the pub.

Puzzled
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 And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
Wayne wrote:
bare with me

Shocked sorry, no, getting naked doesn't help with the science!
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 So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
OK than ,me and Mrs W are having a battle. How do you say in words this number

542,042,882,000,000,000,000,000,000,000,000

I think its 542 million and 42 thousand 882 billion trillion
she thinks something else Puzzled


Yeah it has (sort or) something to do with goggles

Big respect to anyone who can tell me what the number is


PS I'll give you a clue
You'll need the Avogadro Constant and an assumed set atomic mass of 1.01 (hydrogen)
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 You know it makes sense.
You know it makes sense.
5.42042882 times ten to the power of thirty three.

Been too long since I did any Chemistry to say anything sensible about what it might mean though but I do remember:

N(A) = N / n
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 Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
Yeah I would just say it how meh says...
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 Poster: A snowHead
Poster: A snowHead
5.42042882 times ten to the power of thirty two. Or about 0.54 decillion.

This http://www.physicsforums.com/showthread.php?t=607183 reckons its the conversion rate for fusion of hydrogen atoms at the centre of the sun (or something). Not sure how it relates to goggles though Puzzled . Anything to do with Fraunhoffer lines?
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 Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
Its not chemistry, its physics.

I got it wrong anyway Confused (as I am really bad at this stuff). I made an A-Level student high on some cheap cider, type mistake Laughing .

I was trying to get an approximation (sort off, almost, in a round-a-bout type of way, about) of how many H1 are altered to He3 within the core of the sun Puzzled .

See I told you it was (sort of) to do with goggles.
Goggle change the diffused reflection (350nm to 750nm) "sun-light" so the refraction is more “seeable” (can’t think of a better word at the mo).

But when looking at the Hydrogen 1 to Helium 3 (via Protium -> Deuterium -> yada yada yada) in a drunken A-Level student way I didn’t account for the kinetics (so the mass simply ain’t gas is it DOH, its plasma) Sad .

Anyway, blah balh blah after stabbing away on my calculator I have now (I think) got something that’s sort of correct.



Oh and that answer of (on the other forum) 9.2×10^37 is assuming mass but the question was about volume - which for high kinetic plasma has sod all to do with it. But what do I know wink
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