Rupert's Drop
Prince
Rupert’s drops are formed by dropping hot molten glass into cold water.
This gives a drop
like tadpole shape (see the image taken from Creative common licence). The drop
has a strong head and a tail.
This develops
opposing forces of high compressive strength on the outside and high tensile
strength on the inside making the tail incredibly sensitive. Even if you
hit the bulky head portion with a hammer or a hard material it doesn’t break
nor can a bullet pierce through.But if the tail is disturbed, then the drop is
no more hard.
The drop becomes fragile when the tail is distorted. Because of those
opposing forces, a minor distortion to a drop’s tail causes the whole structure
to explode, almost at 1lakh frames /second.
These drops are also called Batavian tears
Prince Rupert's drops were discovered in the 17th century
Rupert of Bavaria presented 5 drops to Charles II of England.
These were turned over to the Royal Society for
study in 1661.
One
significant use: for making tempered
glass for modern smartphone screens
