From: Steven Eiger (eiger@montana.edu)
Date: Sun Nov 26 2000 - 18:44:41 PST
Message-Id: <l03102800b6477455b100@[153.90.150.107]> Date: Sun, 26 Nov 2000 19:44:41 -0700 From: Steven Eiger <eiger@montana.edu> Subject: Re: pinhole Re: frictionless ice
Julie, While I know nothing about ice skating, sometimes I walk, and I live
in Montana. I have noticed that below a certain temperature, probably
about -15 C, the ice is not so slick, and becomes quite safe to Walk on.
Perhaps the pressure increases the layer of water on the surface of ice, at
all pressures and temperatures, and there is a minimum water layer that is
associated with good sliding. Also, when someone sets an edge to push off
from a skate, the pressure becomes enormous, but the blade digs a furrow in
the ice and does not slip, although it must be very slippery in the blade
direction. Since a furrow is dug, this seems to imply that that pressure
is sufficient to liquify the ice? Glass must be another story because I
suspect glass goes to a solid with increased pressure like most things. I
am going to have to find an article about all this, because I really do not
understand a lot of things about this. Steve
>I think that a small layer of water created by dangling bonds is negligible
>compared to the size of a skate or anything we would try to glide on ice.
>Again, there is a comparable layer of water on glass, and we do not
>experience the same phenomenon with pressure on glass. I do believe that
>there must be a certain temperature below which ice skating is not easy,
>though, I too do not have direct experience. I would imagine that it would
>be lower than the -15 C I calculated due to some kind of localized heating
>effects. It would be interesting to see, though, if folks have experienced
>otherwise.
Steven Eiger, Ph.D.
Department of Cell Biology and Neuroscience and the WWAMI Medical Education
Program
PO Box 173148
Montana State University - Bozeman
Bozeman, MT 59717-3148
Voice: (406) 994-5672
E-mail: eiger@montana.edu
FAX: (406) 994-7077
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