The mystery of tiny teardrop-shaped glass confections that can survive a hammer blow, yet shatter to smithereens with the slightest touch to the stem, has finally been solved.
The strange shapes, called Prince Rupert’s drops, have posed a riddle that has stymied scientists for 400 years.
“On one hand, the head can withstand hammering, and on the other hand, the tail can be broken with just the slightest finger pressure, and within a few microseconds the entire thing shatters into fine powder with an accompanying sharp popping noise,” study co-author Srinivasan Chandrasekar, a professor of industrial engineering and director of the Center for Materials Processing and Tribology at Purdue University in Indiana, said in a statement.
Now, a new study reveals that the head of these little glass tadpoles has such indomitable strength because of the compressive forces acting on the outside of the drops. These forces rival the compressive forces in some forms of steel, the study found.