Prince Rupert's Drop

Bolognese tears (also Bolognese glass tears ) or Batavian drops are small, metastable glass drops that are by the nature of their production of such tension that such a drop shatters glass to dust when breaking its tip.

History

In medieval times, glass was heated, drawn out long and then rapidly cooled so that it shattered into a very fine glass dust. Some doctors and pharmacists gave water mixed with this glass dust their patients under the name glass of water as a medicine, which, however, had no medical effect. 1625 was the phenomenon that glass suddenly " explodes into a thousand tiny pieces ," the first to focus more accurately and 1642 the Batavian drops were reinvented with the Bolognese glass bottle in Bologna.

Production

Hot, liquid glass is dropwise added to a container with water or oil to cool.

Physical

The thick end of a Bolognese glass tear can charge up to a certain point; but once you get the thin end only slightly damaged, the strong stress brings a tear to implode. The decomposition front spreading from this at speeds that is higher than the velocity of detonation of black powder. The strong tensions within the tear resulting from the rapid cooling, as the drop hardens from the outside to the inside and because glass shrinks during solidification. Glass, in addition to the shrink properties, depending on the cooling rate. During slow cooling, the glass shrinks more.

Additional info

Toughened, which shatters if damaged in numerous small, rounded parts, works on the same principle. Here, the bias voltage is generated by a heat treatment.

Bolognese bottles work on the same principle. It is thick-walled glass bulb. They are so stable that you can drive a nail into a piece of wood with them. However, you can fall into a nail into the bottle imploded this. Reason, here are the high tension in the glass, the discharge at hurting the surface by the impact of the nail tip.

Literary treatment have found Bolognese tears in the eponymous story Gustav Meyrink (about 1905) and 1988 to published in Peter Carey's novel Oscar and Lucinda.