Why does cooled rubber shatter if you hit it?

There are many types of molecular bonding, some strong others weak....#

If you super cooled steel enough you would shatter it with a sufficient impact.

Remember what happened in the antartic with the radio transmitter towers... They held together with solder / lead tin mix... the tower fell apart in the cold just like the petrol can seams did holding the petrol for the Scott antartic expedition....

John.

tin changes to another allotrope at low temperatures which has little strength

they call it 'tin pest'

This may have been a factor

http://en.wikipedia.org/wiki/Tin_pest

Yes, very interesting article.. and tragic.

-40 C./F. does tend to concentrate your thinking doesn't it? Mainly, what the hell am I doing here! But I've also had a similar experience when the inside plastic door trim on my Chevy shattered upon slamming the door at low temperatures. And being a simple mech. eng. I've also wondered whatever happens to a battery's capacity when cold? Any battery regains strength quite quickly after warming it up. Makes me think about how well an electric hybrid vehicle will function in these temperatures. Are there any elect. eng. out there who can convince me to buy a hybrid?

A rubber in this state is, in effect, a glass. At high temperatures a crack will not propagate because the mobility of the rubber allows stress to relieve. Cool it down and you reach the glass transition temperature = shatter time

http://en.wikipedia.org/wiki/Glass_transition_temperature

Metals can become brittle at low temps for other reasons

Well, I think that this is the answer.. thanks everyone. I was thinking in terms of atoms, and the answer clearly lies more in the realm of molecules, and the geometries at different temperatures... I have a lot to learn here, and thank you for this article.

Chris

Hi Chris

This works the same with a glass of water. if you pour a glass of water on the table and hit it with your hand it will just splash. But if you freeze the water then hit it and it will shatter.

Radar

yes, and when you warm ice cubes close to their melting point they bounce around like rubber cubes. Well water has no glass transition temp. It is either a crystaline solid at 0C or a fluid at 0C, on either side of the heat of fusion energy differential

Well, states of matter are temperature dependent, so maybe this points in the right direction... if a change of state is a rearrangement of valence electrons into a different arrangement, and changes the geometry of the bonding, which of course affects the propagation of shear and fracture forces, or just forces in general, then "Geometry" is maybe part of the answer I'm looking for.

In a conductor with few valence electrons, there would be few arrangements possible, but as you increase the number of electrons, the geometry can change into more differently shaped structures, and therefore cause changes in elasticity and force propagation. hmmm. Does the speed of light through substances change with the temperature? If you chill the water in a radioactive pool, does the color of the light change? I wonder...

ah it doesn't
http://www.youtube.com/user/WSUChemDemo#p/u/20/O6sD6b_3GLg

but if left to long it will explode
http://www.youtube.com/watch?v=yg45ILXZ26w

if you are saying the hammer didnt shatter.. better watch again. in the last few seconds, it does.

thanks for the links.

chris