The 400-Year-Old Mystery of These Bullet-Shattering Glass Drops May Finally Be Solved
The tadpole-shaped glass structures can survive a hammer blow but explode if their tail is squeezed
By Jason Daley
May 15, 2017
Since the 17th century, Prince Rupert’s drops have puzzled scientists. The drops are made by dipping a bead of molten soda-lime or flint glass in cold water, which forms a tadpole-shaped piece of glass. While the head of the drop is incredibly strong and can resist everything from a hammer blow to speeding bullets, just flicking the tail of the crystal can cause the whole thing to burst into powder. Now, as David Szondy at New Atlas reports, researchers have finally figured out the secrets behind these drops.
Back in 1994, researchers used high-speed photography to record and analyze the way the drops shatter, Lisa Zyga reports for Phys.org. They concluded that the surface of the drop has high compressive stress while the interior of the drops is under high tension. While that combo makes the head very strong, it’s not in equilibrium, which means even a slight disruption at the tail causes the whole thing to destabilize and fall apart. In fact, the cracks move at 4,000 miles per hour, which pulverizes the glass.
Read more:
https://www.smithsonianmag.com/smart-news/researchers-crack-400-year-old-mystery-prince-ruperts-drops-180963308/#Wk4XXCEJboV4uUpk.99
