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39838.  Fri Dec 16, 2005 12:46 pm Reply with quote

I needed to find out as much as I could about elastic, because of a sock-related obsession related in the General Banter forum.

My first flirtings were not auspicious. According to Wikipedia, elastomers (as I now understand I must call elastic)

are amorphous polymers existing above their glass transition temperature, so that considerable segmental motion is possible.


Rory Gilmore
39850.  Fri Dec 16, 2005 1:06 pm Reply with quote

It means they're bendy unless it's really cold.

''Elastic'' is more of an adjective, really. An elastic collision is one in which all energy is converted to motion. So really it doesn't exist, except in space or something maybe.

74123.  Tue Jun 13, 2006 4:45 am Reply with quote

Rubber is odd in that it's the shape of the long molecules that cause its elasticity - the 'scrunched-up' molecules straighten out when pulled, but they like to retain their original shape. You're flexing the direction of the bonds on each atom.

For most other materials, it's the length of the bonds between the atoms themselves which you're trying to stretch, so, for example, steel girders are not that stretchy.

Last edited by Gray on Tue Jun 13, 2006 5:04 am; edited 1 time in total

74128.  Tue Jun 13, 2006 4:57 am Reply with quote

Elastin: A protein that coil and recoils like a spring within the elastic fibers of connective tissue and accounts for the elasticity of structures such the skin, blood vessels, heart, lungs, intestines, tendons, and ligaments. Elastin functions in connective tissue together with collagen. Whereas elastin provides elasticity, collagen provides rigidity to connective tissue. Elastin is normally no longer made after puberty and aging begins. Also called elasticin.

74306.  Tue Jun 13, 2006 1:46 pm Reply with quote

Elastin is normally no longer made after puberty and aging begins.

Which is why we get all wrinkly as we age :-(

QI Individual
74585.  Wed Jun 14, 2006 11:03 am Reply with quote

More interesting bits on this subject on the BBC News site.

The chronic lung condition emphysema is also associated with loss of elasticity in the lungs and is analogous to wrinkling in the skin

Professor Chris Griffiths
British Skin Foundation

81931.  Wed Jul 26, 2006 12:54 pm Reply with quote

A QI snippet in today's Guardian caused me to resurrect this thread. The whole thing is interesting, but I was particularly intrigued by the bit I've bolded - no idea how to check the truth of this assertion though:

Q: Why does spinach produce so much water and where does it come from?

A: Nearly all living organisms (including ourselves) are at least three-quarters water and for leafy plant material such as spinach this will be higher, probably more than 90%, which is released during cooking.

But if most of the fresh produce we cook is mostly water, why do some things (such as spinach and mushrooms) release it while others do not? This must be because forces exist in some foods that drive water out of the tissue during cooking. In the case of spinach this is probably because the walls that surround each cell are elastic and are highly stretched by the substantial pressures inside the cells (plant cell pressures are typically two to four times that of a car tyre). When the cells are damaged during cooking, they depressurise and the elastic forces in the cell wall drive water out of them in the same way that air is forced out of a punctured balloon.

In other plants where the walls are less elastic and therefore less stretched, much less water will be released (more like puncturing a football).

82014.  Wed Jul 26, 2006 7:07 pm Reply with quote


Yeah, sure.

Or p'raps a gradual leak instead. Folowed by a reduction in volume. Somehow.


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