Spontaneous Glass Breakage or Shattering

Glass is a strong and robust material, but also fragile at the same time. It is strong along its plane line, however, it is weak to forces acting perpendicular which will cause it to crack along fault lines caused by tiny imperfections in the structure.

Glass can be hardened (tempered) or untempered. Tempered glass is heat treated to withstand greater forces and temperature ranges. Large, fast, changes in temperature can cause it to shatter if it is heated up or cooled down too quickly. This is due to the expansion and contraction caused by heat and glasses' inability to cope (inelastic). Both tempered and untempered glass can suffer from spontaneous glass breakage, although it is much less common in tempered glass.

Nobody fully understands the reasons behind spontaneous glass breakage despite many documented cases, maybe it's even happened to you. If it has, please let us know in the comments below!

Why does Glass Spontaneously Break?

Some theories include microfractures caused by prior impacts or dropping which suddenly give out as the ambient temperature drops or rises. It could be from contact with other items, maybe a glass placed on or near a metal cutlery item or marble surface and vibrations from passing vehicles cause vibrations which cause the two to knock into each other.

Another cause could be harmonic resonance, either sonic or supersonic. Sonic harmonic resonance would be from something like when an opera singer sings a loud continuous note to break a wine glass. Supersonic could be ultra-low frequency or high frequency at just the right frequency and amplitude to resonate the glass. These resonations or vibrations cause the glass to "wobble" ever so slightly and can eventually lead to a failure along any microfractures, chips or other imperfections.

Another common cause believed by many is that the glass is being acted upon by ghosts. Apparently, it is easy for a spirit to make itself known by resonating a glass until it shatters.

Whatever the cause it can be a frightening experience if it happens while you are close by, or indeed see a glass shatter with no apparent cause.

My Experience of Spontaneous Glass Breakage

On the night of 31st May 2018, my fiancee and myself were abruptly woken in the middle of the night to a tremendous smash. Believing that someone has put a brick through a window, or otherwise tried to force entry and broke a window, I quietly checked each room and then each window for signs of entry. Upon finding all rooms empty and all windows intact, I checked the mirrors, photo frames, and display cases, in case anything had fallen off the wall. Alas, these were all in tact. There was no evident cause for the noise. With all the checks done and satisfied that we weren't being robbed we went back to bed.

In the morning I went into the kitchen to make coffee and then noticed the tiny fragments of glass on the floor and over the kitchen worktop.

One of the glasses we were drinking from the night before and placed on the counter for washing up had exploded!

It was an old English pint glass (probably taken from a pub many years ago) that I'd been using for many years. All of a sudden that night it decided to shatter into a million pieces. Not just cracked, but violently exploded. Even the thick base was shattered into tiny shards. We found glass over the countertop, in the sink, over the floor, and even on the window ledge!

Normally when a glass like this is dropped the base at least survives and the walls break off into large chunks. But this was shattered into tiny pieces, much like when a car window shatters and you get millions of tiny crystals of glass.

Whatever the cause it was a scary night to remember.

Have you experienced anything like this? Have any of your glasses spontaneously exploded for no reason? Let us know in the comments below!