Calibrating temperature probes

"Julian Scarfe" wrote in message
...
"Peter Duniho" wrote in message
...

I believe it does. If I recall correctly, the pressure from the blade
of
an
ice skate is what melts the ice and allows the skate to glide easily
across
the ice.

I don't doubt your recall, Peter, as I'm sure I was taught the same.
However, check out:

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

Julian Scarfe


I don't buy the physicist's argument. Blades are curved, so there is likely
ten times less surface area on the ice.
--
Jim in NC

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


"Morgans" wrote in message
...

I don't buy the physicist's argument. Blades are curved, so there is
likely
ten times less surface area on the ice.

....which would make the depression of freezing point 0.2 degC. Still not
enough.

Julian

He is all wet.... Good thing for his employer he is retired.. I hope I
don't use any products he was part of designing...

Skate blades have a rocker bottom, like a boat hull, limiting the area of
steel in contact with the ice, which radically raises the pounds per square
inch of pressure, applied (PSI) at the contact patch... Further, the skating
edge is ground concave, not flat, so that two knife edges raise the PSI to
huge levels at the minute points of contact between the edge(s) and the ice,
liquifying the ice instantly, and the wedging action of the inside profile
of the concavity then squirts the liquid towards the center of the concavity
raising the blade up onto a hydrostatic wedge of water... Same hydrostatic
phenomena that keeps your crankshaft from welding to the rod bearings...
Same logarithmic rise in pressure at the wedge point phenomena that allows a
sharp knife to cut more easily than a dull knife...

As far as unsatisfied hyrdrogen bonds at the interface between ice and air,
I suspect that is true but that is not what makes a skater glide...

Get your kid on skates and take a magnifying glass with you and look at the
fresh skate track and you will see how the ice liquified and then refroze
instantly leaving a different ice surface in the track than on the ice
adjacent to the track... Try the same test with a skate blade ground flat,
or even a little convex, on the bottom (make sure your kid is well
padded)...

Experts!!! ya gotta love em...

Denny
"
Morgans" wrote in message I don't buy the
physicist's argument. Blades are curved, so there is likely
ten times less surface area on the ice.
--
Jim in NC