Residual Stress in Glass - Mystery of Prince Rupert's Drop at 130,000 fps

Residual Stress in Glass - Mystery of Prince Rupert's Drop at 130,000 fps

Mystery of Prince Rupert's Drop at 130,000 fps : Ri Channel

Fellow geeks on the forum may find this interesting. As demonstrated, the very high residual stress within the bulbous end of the drop allows it to withstand a blow from a hammer. However, a slight touch on the drop’s tail will cause the whole structure to explode.

Nice one. There are some good slow motion videos here:
theslowmoguys - YouTube

Very interesting!

The same principle(though less extreme) is used to toughen, or temper, flat glass.
Heat to around 650 deg c , then rapidly cool with blasted air creating tension inside the glass.
Toughened glass is stronger than normal glass (the name's a giveaway!), but is susceptable to defects or impacts from sharp pointed implements.
One of the principle benefits is the fact it breaks into lots of small fragments that are much safer than annealed glass.

Then you just have to watch this by the same guy on the Worthington Jet -

Just love the "Number 2 version" of the projectile and the Question/Response

Q) Are those beads?
A) Technically

Poop Splash Elimination - Smarter Every Day 22 - YouTube

:-)