Prince Rupert's glass drop shatters flying bullets

Enthusiasts from the Smarter Every Day channel conducted an interesting experiment with a famous physical phenomenon called "Prince Rupert's drop". It is a glass product that forms when a mass of glass is allowed to drain freely into a container of water. The result is a long-tailed bulge that is so strong that it cannot be broken with a hammer. But what about a direct bullet hit?

The YouTubers conducted an experiment in which they fired point-blank at a drop from small-caliber firearms. They used a camera at 15, 000 frames per second to see the process in detail. It turned out that the bullet is powerless against Rupert's drop, but sometimes it provokes its detonation, followed by instant destruction.

The peculiarity of the Rupert drop is that when it solidifies, a colossal surface tension is created in it, which is so strong that the kinetic force of the bullet is not able to overcome it. Moreover, the shooting experiment showed that the bullet literally falls apart on impact, while the drop remains conditionally intact. But not for long - after a few fractions of seconds, the drop itself is destroyed.

Destruction of a drop from vibration

The reason is that vibrations from a collision with a bullet propagate along the surface of the droplet and reach its fragile tail. Having broken, it releases the accumulated energy, which literally explodes the seemingly so strong drop.