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Dutch Tears

October 22, 2013

Let’s talk about Dutch tears. These are better known as Prince Rupert’s drops, but I didn’t want you sickos to think I was writing about obscene body art so I went with their second-most popular moniker. I first learned about them when I saw a video by Smarter Every Day (the same people that filmed cats flipping while they fall lol). Anyway, Dutch tears are made by dropping molten glass into cold water – basically just allowing a big blob to plop right in and cool. There’s not a real science behind it, it pretty much counts as a Dutch tear as long as it looks like a sperm.

How baby glass is made

So we all know that dropping hot glass into cold water will cause it to rapidly cool and solidify, right? Well, this cooling happens on the outer part of the droplet first – the part touching the cold water – which means it hardens before the core of the drop. The cold outer glass constricts while the molten center is still hot and “swollen.” As the center cools it also constricts and starts to pull inward, but the outer portion is already rigid and inflexible. This creates a buttload of tension, almost like a giant arm wrestling match that never ends.

So…. why do you care? Well, these things have a crazy trick up their sleeve. You can’t smash the bulb no matter how hard you try! Well, I’m being sort of misleading. It’s hella hard to break the bulb, but if you try you’ll probably have a scenario just like this… where the bulb resists the impact but moments later the entire thing completely explodes:


So, I wasn’t lying to you when I said the bulb couldn’t be broken… the failure here actually occurs in the tail. You see, the structure of the bulb is so strong that compression in any direction is opposed by the tension all over the structure. So no breaking. However, you can see the glass move and wobble up near the guy’s fingers, which is a part of the structure with far less structural oomph. As the glass in the tail gives way, it allows for all that teen-angsty tension to be released in a wave down toward the bulb. It doesn’t just crack, it blows up. At 1600 meters per second… or 3579.1mph.


So the end result is an awesome explosion of glass shards in all directions. I like to imagine the first guy who figured this out by accident… like oh I’ll just toss this useless glass chunk over there… OH GOD WHAT THE HELL WHY DID IT EXPLODE?! Heh. Awesome.

Anyway – go make your own and have fun. Wear goggles sillies. 🙂



From → Physics

One Comment
  1. William permalink

    I don’t really have anything constructive to add, but that was pretty fucking awesome!

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