Duke Rupert's Dutch tears
Duke Rupert's Dutch tears

Video: Duke Rupert's Dutch tears

Video: Duke Rupert's Dutch tears
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Anonim

If you drop molten glass into cold water, it will solidify in the form of a tear with a long, thin tail. If you break off the tail of such a glass tear, it will immediately explode, scattering the finest glass dust around it.

Glass tears were invented in Germany in 1625. In the 17th century, it was believed that glass tears were actually invented in Holland, so they began to be incorrectly called "Dutch".

In Britain, glass tears became famous thanks to the British Duke Rupert of Palatinate. He presented them to King Charles II, who, in turn, presented them to the Royal Scientific Society for research. In honor of the duke, glass tears began to be called "Rupert's drops." The method of making Duke Rupert's drops has been kept secret for a long time. They were sold to everyone, like funny toys.

Today the mechanism of Dutch tears "work" has been thoroughly studied. If molten glass gets into cold water, it quickly solidifies, building up incredible mechanical stress. Let us conditionally select the outer layer and the inner core in the drop. The drop cools from the surface, and its outer layer is compressed and reduced in volume, while the core remains liquid and hot.

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After the temperature inside the ball drops, the core will begin to shrink. However, the already solid outer layer will resist the process. With the help of intermolecular forces of attraction, it tenaciously holds the nucleus, which, when cooled, is forced to occupy a larger volume than if it cooled freely.

As a result, forces will arise at the boundary between the outer layer and the core, pulling the outer layer inward, creating compressive stresses in it, and the inner core outward, forming tensile stresses in it. These voltages are very significant when cooling too quickly. So that the inside of the ball can break off from the outside, and then a bubble is formed in the droplet.

If the integrity of the surface layer of the teardrop is violated, then the force of tension will be immediately released. The solidified glass droplet itself is very strong. It easily withstands hammer blows. However, if you break its tail, it collapses so rapidly that it looks more like a glass explosion.

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