SpeedyWilson Loc: Upstate South Carolina

This is an interesting video of a special kind of breaking/shattering glass, and a scientific explanation:

http://videos.komando.com/watch/3106/kims-picks-incredible-exploding-glass

CJartist Loc: Ormond Beach

Thanks for posting that was very interesting and enjoyed it very much.

2MATO Loc: CNY -Central NoWhere

Excellent link to some great stuff. I subscribed and hope to get-smarter-every-day. :mrgreen:

Thanks for sharing such a rich resource.

Big Stopper Loc: London

Thanks for sharing - found that fascinating, Bob

rcirr Loc: Gilbert, Arizona

Great link...very interesting.

Terrymac Loc: LONDON U.K.

Most interesting. Thanks.

twna Loc: Western Colorado

Fascinating, Thanks for sharing.

flathead27ford Loc: Colorado, North of Greeley

Wow! I had never seen anything like that before. Very interesting. Thanks for sharing it with us. Cheers.

iDoc Loc: Knoxville,Tennessee

Thanks for the link. Most interesting.

Toby

The video is a really excellent job of explaining a common phenomenon of glass that has changed your world even though you may not have known it. A bit more science: glass only breaks when it is in tension. That is why he can hit the Prince Rupert drop with a hammer without breaking it. The drop has a very high compression layer around it and unless you break thru the compression layer to the tension layer inside you will not break the glass. It is much easier to snap the thin “tail” off of the drop which exposes the tension layer. When that happens the fracturing of the glass in the tension layer travels at nearly the speed of sound. So what does this have to do with your everyday life? Well, the side windows and backwinds in your car are fabricated in much the same way as a Prince Rupert drop. The difference is that the glass is rapidly cooled with air. In the US this glass is called “tempered” in Europe it is called “toughened’.
Ever notice how hard it is to break a side or back window in your car versus the windshield or a pane of glass in your house? It is because the tempered glass has the protective compression layer that must be penetrated before the glass will break. Once it does glass fractures travel thru the entire piece until all stress is relieved. Why don’t they make windshields out of this stronger glass? Because when it breaks the entire piece breaks and vision thru it would be compromised. (I know there are ways to semi-toughen or anneal select areas but I am not going to get into that. I have bored you long enough).
A final note; ever notice the streaks in a car door or back window glass on a sunny day? That is called irradiance and is directly related to the stress in the glass. It is particularly noticeable if you are wearing Polaroid glasses and it is a sunny day. Just as you get a polarized reflection of a shiny surface (water for example) you can get one off the glass. Rotate your sunglasses and watch it change.

Terrymac Loc: LONDON U.K.

So exactly as it showed in the video.

joehel2 Loc: Cherry Hill, NJ

Thanks for posting the link.