Why glass explodes if it’s exposed to a sudden temperature change.
In: Chemistry
It does not necessarily explode, however when the glass temperature changes unevenly parts of it will expand faster than others. Glass is not stretchy – it is incredibly non-stretchy. The result is a tearing/cracking. If the force is sufficiently high, or if parts if the glass are already stretched, it may explode.
Glass is a strong, but brittle material. It does not want to bend, dent or stretch.
When an object is heated or cooled, it expands or contracts respectively. If this is done perfectly, you just end up with a slightly different size, but in the real world, there are variations in temperature that introduce stress into the piece as it doesn’t fit its own structure.
If those variations are significant enough, the piece overcomes its strength and deforms. For metal, the piece simply twists and warps to the new shape, but for glass, the material does not tolerate that warping, and instead the stress builds internally until the piece breaks. Because of the strength of the glass, a lot of energy has built up before this break, meaning there’s a lot of force released in the break, causing the glass to “explode” catastrophically.
You can compare the behavior to clay ceramics, which are not as strong, but still exhibit brittle behavior: Under the same circumstances, a metal pot will warp, a clay vessel will crack, and a glass vessel will shatter.
You know how things expand/contract when heated? That also happens with glass. If it happens slowly then all parts expand at the same time, so it’s fine.
If you take a hot (expanded) glass and hit it with cold water, the parts touched by the water shrink while the other parts don’t. If some part of the glass tries to be shorter than another part that it is attached to, something needs to give. Other materials (like metals) can bend, so they’re fine. Glass can’t bend so well, so it breaks.
You know how things expand/contract when heated? That also happens with glass. If it happens slowly then all parts expand at the same time, so it’s fine.
If you take a hot (expanded) glass and hit it with cold water, the parts touched by the water shrink while the other parts don’t. If some part of the glass tries to be shorter than another part that it is attached to, something needs to give. Other materials (like metals) can bend, so they’re fine. Glass can’t bend so well, so it breaks.
It’s called thermal stress and you need special glass to effectively resist it. Borosilicate glass is a good first step.
Latest Answers