Wes;
I know that looks dramatic but I don't think it says much about its
elasticity.
The physics term "elastic" is almost universally misunderstood. Common usage
has changed the word's meaning over the years and this causes those
misunderstandings.
A material is "elastic" if it rebounds close to 100% from being deformed.
For example, valve springs are highly elastic; their rebound is close to
100% but not exactly 100%. They lose a tiny bit of energy when a valve is
opened & closed; at high RPM, this energy loss is high enough to get the
springs so hot that they need to be cooled by the oil.
Most people think that a rubber band is elastic but that isn't true. It is
"stretchy" but not very elastic. If you quickly stretch a big rubber band
across your fingers, you can feel the heat from the energy loss due to
deformation.
Actually, glass-- of all things-- is very elastic. If you bend a sheet of
glass, it will spring back with close to 100% rebound. Bend it too far and
it shatters. It goes from a region of elasticity to rupture with no
"plastic" range.
A good test of elasticity is to drop a ball of a material on a smooth hard
surface such as steel and see how high it bounces. A glass ball will bounce
higher than one made of rubber-- up to the point where the glass breaks into
smithereens.
Just where the salt fits into the "elastic" picture, who knows? I've gone on
far to much about this-- sorry.
Regards, Neil
-----Original Message-----
From: W S Potter [mailto:wester6935@comcast.net]
Sent: Wednesday, August 13, 2003 6:38 PM
To: Albaugh, Neil; 'DrMayf'; 'Dave Dahlgren'
Cc: 'land-speed@autox.team.net'
Subject: Re: Bonneville Request
The pressure ridges tell me NO!
Wes
on 8/13/03 11:58 AM, Albaugh, Neil at albaugh_neil@ti.com wrote:
> Mayf;
>
> As Dan suggested, maybe the beer can rebound test will supply enough
> data.
>
> I don't think salt is "soft" but the question is "is it "elastic" in
> the strict physics definition?"
>
> Regards, Neil Tucson, AZ
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