Prince Rupert's Drops or Dutch tears Prince Rupert's Drops
or Dutch tears
are drops of tempered glass, characterized by huge internal tensions.
These particular drops, with the form of a tear-drop tapering to a fine tail, are obtained when molten glass drips into cold water.
In contact with water, the glass cools immediately.
This extreme hardening causes enormous tensions in the glass drops that give rise to their particular properties, such as the ability to withstand hammer blows given to the bulbous part of the drop. Instead, even a small scratch on the "tail" results in the quick release of enormous amount of potential energy
stored in the internal structure, causing fractures that propagate through the glass toward the head at such high speed that the entire structure explodes into a fine powder.
An examination of the shattering of Prince Rupert's Drops
by the use of high speed video has revealed that the "crack front" which is initiated at the tail end propagates in a disintegrating drop within the tensile zone towards the drop's head at a very high speed
[1.45–1.9 km/s (0.9–1.2 mi/s)].
Although the mechanism that underlies the glass tempering was not known before the twentieth century, the effect is instead known for centuries. In 1640, Prince Rupert of Bavaria
brought to the attention of the King the discovery of those that are known since then as the "Prince Rupert's Drops."
The drops were used as a joke: the King did to hold in the palm of your hand the drop from the part of the bulbous, then he broke the tail causing a small explosion that astounded the victim of the joke.
It is not difficult produce them, but you must be cautious.On 4 March 1660-61
"glass bubbles" were first introduced to a meeting of the Royal Society of London
. Read the abstract relating to a General Colloquium
from Professor Srinivasan Chandrasekar
, Purdue University: http://www.physics.purdue.edu/colloq/99-00/chandrasekar.html
The drops were also immortalized in a verse of the Ballad of Gresham College
(1663):And that which makes their Fame ring louder
,With much adoe they shew'd the KingTo make glasse Buttons turn to powder
,If off the[m] their tayles you doe but wring
.How this was donne by soe small ForceDid cost the Colledg a Month's discourseDorothy Stimson
, Ballad of Gresham College
.Scientists and Amateurs
: A History of the Royal Society
(1948) - pag. 59: http://books.google.it/books?id=cj8eAAAAIAAJ&q=%22To+make+glasse+Buttons+turn+to+powder%22&dq=%22To+make+glasse+Buttons+turn+to+powder%22&pgis=1Watch
:Mystery of the Prince Rupert's Drop - Smarter Every Day 86
, a video demonstrating the creation, processes, explanation, and multiple high speed recordings of a Prince Rupert Drop.: Mystery of Prince Rupert's Drop at 130,000 fps - Smarter Every Day 86
The animated gif was extracted from this video.Watch also
Video showing the making and the breaking of Prince Rupert's Drops from the Museum of Glass:Prince Rupert's Drops!Further reading
Popular Science article with video detailing Prince Rupert’s Drops: http://www.popsci.com/diy/article/2008-06/shattering-strongest-glass#physics #scientific_curiosity #science #sciencesunday #scienceeveryday #scienceongoogleplus