I'm fascinated by Prince Rupert's Drops, those super strong blobs of glass that look like tadpoles. We've written about them in the past here at Boing Boing, but I thought I'd share some newer videos showing how they stand up to things like bullets and hydraulic presses. Spoiler alert: they do shockingly well!
First off, if you're new to Prince Rupert's Drops, here's a brief overview:
To make a Prince Rupert's Drop simply drop a blob of molten glass into cold water. Like many other things, glass shrinks as it cools. When a blob of melted glass is put into water the outer layer cools and becomes rigid while the inside is still liquid. As the interior liquid glass cools it pulls the rigid outer layer inwards creating an incredible compressive strength of 13,000–25,000 PSI. It's the same idea as how an arch gets stronger when more weight is put on it.
Next, here's a very cool short posted by Science Explained showing a hydraulic press trying to crush a Prince Rupert's Drop. The press is unable to shatter the glass and gets bent, instead. This particular press is likely made with a softer metal than other hydraulic presses, but even when standard presses do eventually shatter them—like the ones in this video posted by the Hydraulic Press Channel—it often takes a great deal of pressure, and they also usually become bent in the process.
Finally, here's an amazing video of some Prince Rupert's Drops not even shattering when shot at by bullets. These things are just wild! Physics, am I right?!
Enjoy! And learn more about the Prince Rupert's Drops in this short video by Purdue Engineering.
