Since it was invented by humans, glass has gradually played an important role in human life, and now it is possible to see and use various glass products almost every day.
Glass gives people the impression of transparency, beauty, and fragility, but there is such a glass product, may subvert your perception of glass fragility.
Heat an ordinary piece of clear glass to about 600 ° C, at which time the glass will begin to soften and appear brushed.
At this time, let the softened glass slowly sag under the action of gravity, and the last part of the glass will naturally fall off, so that this part of the fallen glass will fall into the ice water.
Let it cool quickly and immediately solidify into a tadpole shape with a special tadpole shape, a process similar to the process of making tempered glass in modern times.
When the glass is completely cooled and formed, it will become a tadpole with a round head and a long tail, which is a very interesting little gadget, and people call this thing "Rupert's Tears".
Rupert's Tears, seeing this name should be very interesting, according to records, in the United Kingdom there is a very fond of playing with glass prince, he accidentally made a small tadpole-shaped glass, and in the process of making it is like a tear, so some people call this new thing "Rupert's Tears".
Later, people found through research that this is not a simple glass, it also has very unique characteristics, this tadpole-like small thing, not only has a very hard round head, but also a very fragile tail.
The round head of Rupert's Tears is particularly hard, and an ordinary piece of small glass is shattered with a single blow, while the round head of Rupert's Tears cannot be broken with a hammer.
The study found that Rupert's Tears round head, per square centimeter can withstand 7 tons of pressure, which gives it the strength of some special steel.
Compared with the hardness of the round head, its tail is extremely fragile, even more fragile than ordinary glass, and even the tail can be broken by hand, and with the broken tail, it will also make the round head break together instantly.
That is to say, the head of Rupert's tears is very hard, and the tail is extremely fragile, if the tail is destroyed first, the entire Rupert's tears will also break up instantly, study the surface, by shooting the shattering process at a speed of nearly one million frames per second, you can see the crack spreading and disintegrating from the tail at a speed of more than 1500 meters per second.
Although researchers have been trying to figure out what caused these Rupert Tears to possess these unusual properties, it was not until the use of modern technology and equipment that researchers were able to fully understand the principles.
At the end of the last century, Purdue University and cambridge university in the United Kingdom observed the breaking process of Rupert's tears using high-speed tile photography techniques; the conclusion from their experiments is that the surface of each drop of Rupert's tears is subjected to high inward pressure, while the interior is subjected to high inward pulling force, so a strong protective layer is formed on its surface.
However, another question arises as to how the pressure is distributed throughout Rupert's Tears, making them unevenly distributed throughout Rupert's Tears.
Rupert's Tears are easily made by melting hot glass and dripping it into ice water, because the glass droplets can be rapidly cooled and formed in water and do not need to be reprocessed.
In the process of cooling, the first is the external rapid cooling molding, and the interior will cool slowly, that is, the outside will cool faster than the interior; when the outer layer is hardened, the interior will shrink during the cooling process and cause tension to the cooled outer layer, which will make the outer layer harder.
The entire Tears of Rupert are kept in balance by this hard shell, so it is difficult to break it as long as the balance is maintained, and this surface protective layer is still very thin, about 10% of the diameter of the entire round head.
However, its tail is unusually fragile, because although Rupert's Tear Tail also has a hard outer layer, it is too thin, and the hard shell area is smaller, so the force required to destroy it is much smaller, and it is more prone to cracks.
As long as one of the protective layers of Rupert's Tears is broken, cracks will appear, which will break the balance of internal tension and pressure, resulting in total fragmentation, so when cracks appear in the tail, they will quickly extend to the round head, causing the entire Rupert Tears to break.
And how hard the round head of Rupert's Tears is, many foreign partners have exhausted a lot of ways to destroy it, just take a look at it.
Knocking with a hammer doesn't react at all
Bullets can't completely shatter them either
Finally try it on the hydraulic press
So fierce, do not put the hydraulic press in the eyes at all, it should be the iron block below the soft point.
Try another piece of iron, and finally it broke.
In fact, Rupert's Tears is not only structurally interesting, its principles are used in many areas of society, for example, the commonly used tempered glass is made using its principles.
The manufacturing process of tempered glass is very similar to Rupert's Tears, which is also to heat and melt the glass raw materials, and then let it cool rapidly, which will also make the surface of the tempered glass cool rapidly, and after slow cooling, the internal pressure and tension will be formed.
This gives the tempered glass a lot of strength, and after breaking, there will be no lumps or angles, but small pieces and cracks that radiate out.
Although the tempered glass is strong, it also has a fragile place, that is, the edge, and this is the same as the tail of Rupert's Tears, as long as the structural balance of the protective layer on its surface is broken, the whole glass will be completely broken.
Therefore, when some places need to destroy the tempered glass to escape, you only need to destroy the edge of the tempered glass first, and you can break the whole glass.
Many people think that glass was invented in modern times, but in fact it has been invented for thousands of years and serves human beings in all fields of society.
文中图片截取自Youtube《Why is a Prince Rupert's Drop so Hard to Break Science Max》
文中gif截取自Youtube《Mystery of Prince_Rupert's Drop at 130000 fps Smarter Every Day 86《How Strong Are Prince Rupert's Drops Hydraulic Press Test!》《38 Special vs Prince Ruperts Drop at 170,000 FPS - Smarter Every Day 169》