Re: Olympics curling question

[Bernard Cleyet <anngeorg@PACBELL.NET>]

Am I the only one who thinks sweeping does not melt ice?

                            Basal Sliding

Basal sliding, the second way ice moves, can happen several different ways.
True basal sliding means that the base of the ice sheet is near the pressure
melting point, and that some water is present. The pressure melting point is
reached because high pressure actually reduces the temperature at which ice
will melt. Ice at base of a 2200 meter (1.36 miles) thick ice sheet, will melt
at -1.6°C (29.12°F), rather than at 0°C (32°F). The thicker the ice, the lower
the temperature at which it will melt, and the higher the chance that some
water will be available at the glacier base to enhance movement. Large parts
of the West Antarctic Ice Sheet are at the basal melting point, so there may
be large areas under the ice sheet where a thin water layer exists.

http://www.glacier.rice.edu/land/5_icemovement.html


I did a quick calc. for the slope of the p-T curve using the C-C eq.  I got
(using  3.34 E5 J / kg and delta V -9.05 E-5 m^3 / kg) ~-135 atm. / deg. K.
I calc'd that a skater's skate contact width must be < 10 mills for ice to
melt from - 2 deg. C.  As a Brit would say, not bloody likely.

some confirmation:  http://www.physlink.com/Education/AskExperts/ae357.cfm

bc



Michael Bowen wrote:

> At 15:36 2002/02/15, Cliff Parker wrote:
> > I checked this site last night but found no answers to my questions.  Am I
> > missing something?
>
> A quote from the glossary page [http://www.usacurl.org/glossary.html]:
>
> =====
>
> SWEEPING - players sweep to make the rock travel farther or to keep it from
> curling more than desired. Good sweepers can increase the distance a stone
> travels by as much as 15 feet. Sweeping creates a thin film of water under
> the rock, allowing it to glide easier. Two players are ready to sweep each
> shot.
>
> =====
>
> Apparently, the "rocks" can also be made to curve (curl?) to hit or avoid
> other rocks that have already been played, by twisting on the handle as
> they are released. Ice conditions affect the amount of curvature that can
> be achieved.