[latebind (OP)]

Dear Naked Scientists.

If I drop even just a simple drinking glass, it makes a loud noise as it shatters. Windows make a even bigger noise as they break.

Why does glass make this loud noise?

[lightarrow]

I think it's because it breaks very suddenly, due to its intrinsic hardness; this makes the air close to it move very suddenly too, and the noise is then violent and characteristic. Molecular bonds inside glass are of covalent type, so they are like very hard, little strings and so they accumulate tensile strenght until they break all at once (differently from a metal, where bonds are quite different).

[AllenG]

Given that glass is a good resonator I would guess that the shards of glass also act as resonating boards amplifying the sound.