* Thermal Shock: Glass, especially those without boron, has a low thermal conductivity and a relatively high coefficient of thermal expansion. This means it heats up and cools down slowly and expands/contracts significantly with temperature changes.
* Uneven Cooling: When the hot beaker is plunged into cold water, the outer surface cools much faster than the inner part. This creates uneven contraction, leading to significant internal stress within the glass.
* Fracture: The internal stress eventually exceeds the glass's strength, causing it to fracture or shatter.
Why boron-containing glass is different:
Borosilicate glass (like Pyrex) contains boron oxide, which increases the glass's resistance to thermal shock. Boron oxide lowers the coefficient of thermal expansion, meaning it expands and contracts less with temperature changes. This makes borosilicate glass less prone to shattering when exposed to sudden temperature changes.
In summary:
While borosilicate glass is designed to withstand thermal shock, regular glass without boron is extremely vulnerable to shattering when subjected to a rapid temperature change.
