Please solve this mystery????

Why do car windscreens freeze up while most of the other windows on the same car don't (or to a much lesser degree)? The same seems to apply with condensation.

It's like there's some universal rule... ah he needs to see through that front one most!!!

My first thought is that car windshields are not as vertical as the side windows. Gravity moves the snow/ice down off the side windows. The front windshield (some more than others) have a degree of slope less than straight down.

wingnprayer wrote:

Why do car windscreens freeze up while most of the other windows on the same car don't (or to a much lesser degree)? The same seems to apply with condensation.

It's like there's some universal rule... ah he needs to see through that front one most!!!

Standing still or moving??

I found this site... look at posts number 15 and 25.

http://scienceblogs.com/principles/2009/11/a_question_about_frost.php

That is pretty interesting reading.

Gene... they mention "Lee effect" or something like that. That sounds like an aerodynamical term. Any help on that?

The lee side is the side of an object which is facing directly away from the wind, i.e. if the wind is blowing from the North, the South side of the object is the lee side.
The term was/is used still in Nautical circles, especially with sailing-boats.

A command on a boat with sails is, "Helm a-lee" which means moving the tiller away from the wind, thus turning the boat into the wind (to slow or stop it).

The opposite side is the windward side - one should always throw the rubbish, pee or spit on the lee side of the boat or whatever's being thrown over will come back on the boat!

If a small boat is in distress in rough seas, a large ship may come and 'form a lee', a slightly calmer patch of water round the boat, by putting itself between the boat and the direction the wind is coming from.

The frost will probably form on the lee side as the air there is still.
The converse is true of snow because of the 'shadow' on the lee side.
Certainly, the slope of the windscreen will encourage frost to form; I wonder if it has anything to do with the wind flowing across the surface, a bit like a heat-exchanger.
I know for a fact that the tops of my thighs get coldest when riding as the wind rushes along the top of them from knee to hip.

MikeO wrote:

The lee side is the side of an object which is facing directly away from the wind, i.e. if the wind is blowing from the North, the South side of the object is the lee side.
The term was/is used still in Nautical circles, especially with sailing-boats.

A command on a boat with sails is, "Helm a-lee" which means moving the tiller away from the wind, thus turning the boat into the wind (to slow or stop it).

The opposite side is the windward side - one should always throw the rubbish, pee or spit on the lee side of the boat or whatever's being thrown over will come back on the boat!

If a small boat is in distress in rough seas, a large ship may come and 'form a lee', a slightly calmer patch of water round the boat, by putting itself between the boat and the direction the wind is coming from.

The frost will probably form on the lee side as the air there is still.
The converse is true of snow because of the 'shadow' on the lee side.
Certainly, the slope of the windscreen will encourage frost to form; I wonder if it has anything to do with the wind flowing across the surface, a bit like a heat-exchanger.
I know for a fact that the tops of my thighs get coldest when riding as the wind rushes along the top of them from knee to hip.

The bigger service naval vessels still use the term 'Lee'. For example if effecting a rescue or coming alongside another vessel in trouble the naval vessel will position itself with the other ship/vessel in the 'lee' or sheltered area now made by the larger naval ship.

Hope that makes sense.

I still use the term when positioning my Wing in my garden.
The Wing is always positioned in the 'lee' of my garage thereby sheltering it from the winds and weather.

Waspie... when "positioning my Wing in my garden", how deep do you dig to plant it? Here in the states the EPA has all kinds of regulations about disposing of lead, plastic, tyres ( ) and other environmentally unfriendly materials. I had never thought of positioning my wing in my garden, but that is a great suggestion if I can pull it off.

Merry Christmas my friend.

Opalsboy wrote:

Waspie... when "positioning my Wing in my garden", how deep do you dig to plant it? Here in the states the EPA has all kinds of regulations about disposing of lead, plastic, tyres ( ) and other environmentally unfriendly materials. I had never thought of positioning my wing in my garden, but that is a great suggestion if I can pull it off.

Merry Christmas my friend.

Gary, I found up to the axles in a good fertile soil best but the odd dressing of forest bark aids keeping bugs down.

I haven't noticed any growth yet but it's early days.

Seasons greetings

Doug