What makes Glass break?

Question

in idiot terms PLEASE!

Answer 1

On a recent camping trip, we put an empty glass bottle into the fire to try to melt it. It half melted into an interesting shape. We fished it out and allowed it to cool. After it had completely cooled it had micro cracks all over it. The next day, with no outside influence, the bottle broke from the internal stresses that it got in the fire. Glass is an amorphous material. It is actually a supercooled liquid. A plate glass window will get a wider thickness on the bottom and a thinner thickness on the top. It takes a very long time for the thickness to be noticeable. but it will eventually flow down into a puddle. This will take about 200,000 years.

Glass, basically, is very brittle. Brittle materials break easily.

Answer 2

Strangely enough... there are lots of theories, but no generally accepted answer...

"After 2,000 years of making and breaking glass, one might think there would be a definitive answer. But at the Third International Workshop on the Flow and Fracture of Advanced Glasses, held Oct. 2 to 5 at The Penn Stater Conference Center Hotel, 50 or so of the world's top glass scientists scratched their heads as researchers presented sharply conflicting views on the topic."

Answer 3

First I'll give it to you in non-idiot terms, directly from my own lecture notes:

From his analysis of a center-cracked semi-infinite panel, Griffith (1920) proposed a fracture criterion for elastic (brittle) materials. It was based on the release rate of elastic strain energy, offset by the rise rate of interfacial free energy, resulting from crack extension under load. Griffith validated his theory by introducing flaws of varying size into glass panels and then measuring the tensile stress at which they failed.

Now in "idiot" terms, as you requested:

When you apply load to a piece of glass, or simply drop it on the floor, you're asking it to momentarily store something called elastic strain energy. (This is basically the same sort of thing you're doing as when you stretch out a coil spring or a rubber band.) However, if by crack extension the glass can release that energy (which it wants to do) at a rate faster than that of the increase in interfacial energy required to form two new fracture surfaces covered with broken interatomic bonds... it will break.

So, why doesn't it just plastically deform, converting elastic strain energy to plastic strain energy, as most metals would do? It's because the interatomic bonds in glass simply cannot do what those in metals do. (There's a lot more to be said about this, but I think I'll spare you.)

Anyway, since the per-unit-area interfacial energy for glass is essentially constant, the only real variable involved here is the quantity of strain energy you're trying to put in. In practical terms, the more strain energy you ask it to store, the more likely it is to break. In really practical terms, the more load you apply, or the greater the height from which you drop it, the more likely it is to break.

I hope this helps without being too much info.

Answer 4

Glass is only one items in material. Usually the harder the material to more brittle it is. Breaks occurs when you inject power that exceeds the power that hold the atoms into a structure. Usually it is done by collision (hiting with another massive object= a hammer will break the glass)
When you drop it on the floor it will break depending how it hits the floor.

Answer 5

A 20 kilogram rock traveling at velocities greater than 5 kilometers/H~ or a Opera singer that is louder than 135 Decibels~ that matches the harmonics of the shape of said glass!

Answer 6

When glass is stressed beyond its elastic limit it will break. With slow stressing, it is actually plastic, so it will deform, however in most instances in life, overstressing it will break it.

Answer 7

most of the time dropping it.

Answer 8

a brick

Answer 9

if you drop it into your dirty laundry!! thong