How Prince Rupert's Drop Was DiscoveredOnce in Holland, a scientist unknown to us conducted some interesting experiment. But they are also called 'Batavian tears' and here's why. Some sources indicate that they were invented in 1625 in Germany. Opinions regarding the origin of Prince Rupert's drops are very diverse. The round part of such a tear is heavy-duty glass, and its tail is its Achilles' heel, which, breaking off, turns the entire structure into dust. Prince Rupert's tear, Batavian or Dutch drops, devil's tear are all names for the same thing. The windshield for cars is made multi-layered (triplex): two or more layers are glued together with a polymer film, which, upon impact, holds the fragments and prevents them from flying apart. Tempered glass in the automotive industry is used for side and rear windows. Ordinary “raw” glass shatters into large sharp fragments that can seriously injure you. In addition to increased strength, such glass has a serious safety advantage: when damaged, it breaks into many small pieces with blunt edges. The same principle underlies the manufacture of tempered glass, which is used, for example, in vehicles. The speed of this wave is 1.5 km/s, which is five times faster than the speed of sound in the Earth's atmosphere. But if, nevertheless, its surface is damaged by breaking the outer layer, the latent force of tension will be released, and a rapid wave of destruction will sweep from the place of damage along the entire drop. This opposition makes the drop stronger than steel. In this case, the inner part can even break away from the outer, and then a bubble forms in the drop.

As a result, on the border between external and inner layer there are opposing forces that pull the outer layer inward, and a compressive stress is formed in it, and the inner core outward, forming a tensile stress. With the help of intermolecular forces of attraction, it holds the cooled core, which is now forced to occupy a larger volume than if it had cooled freely. When the inner part also cools, the core begins to shrink, but this is now counteracted by the already frozen outer layer. The outer layer of glass solidifies quickly, decreases in volume and begins to put pressure on the still liquid core. In this simple technology lies the secret of the strength and weakness of the drop. The technology for making the drop was kept secret for a long time, but in the end it turned out to be very simple: just drop molten glass into a bucket of cold water. In 1660, Rupert of the Palatinate returned to England after a long exile and brought with him unusual glass drops, which he presented to Charles II, who transferred them to the Royal Society of London for research. The drop got its name in honor of the commander-in-chief of the English royal cavalry, Rupert of the Palatinate, popularly known as Prince Rupert. This curious property of a glass drop was first discovered in the 17th century, either in Denmark, or in Holland (hence another name for them - Batavian tears), or in Germany (sources are contradictory), and an unusual little thing quickly spread throughout Europe as a funny toy. But it is worth slightly breaking the fragile tail, and the whole drop will shatter into small fragments in the blink of an eye. The drop head is incredibly strong, it is very difficult to mechanically damage it by compression: even strong hammer blows or a hydraulic press do no harm to it.

Prince ruperts space drop made in space