If you don't know what a Prince Rupert Drop is, it is a toughened glass beads created by dripping molten glass into cold water, which causes it to solidify into a tadpole-shaped droplet with a long, thin tail. (from Wiki) Posted on 05/19/2017 6:12:25 AM PDT by w1n1
If you don't know what a Prince Rupert Drop is, it is a toughened glass beads created by dripping molten glass into cold water, which causes it to solidify into a tadpole-shaped droplet with a long, thin tail. (from Wiki)
A Prince Rupert's Drop has a reputation of being virtually indestructible; but what will a .38 special round do to it?
If you haven't seen one before, a Prince Rupert's Drop is an amazing feat of engineering that can stand up to a ton of pressure. In the past we've already discovered that even being shot point blank with a .22 will do next to nothing to one, but now Destin from Smarter Every Day has decided to step up his game and give it a try with a .38 Special. See the prince rupert drop shot footage here.
Yes, that usually happens when you shoot Prince Rupert with a .38 Special.
And he even drops faster with a .38 Ordinary!
Do you have Prince Rupert in a can?
Why yes! (But that is now a hole can.)
If this guy isn't a teacher, he should be.
The Prince Rupert Drop and the backwards steering bikes are the most memorable.
Let him out.
Dustin has used the high speed cameras for lots of videos but firing guns just looks cooler when at 10,000+ fps.
There’s some neat physics going on.
Glass has crazy-high compressive strength. Picture how much weight you could set on a piece of glass on a flat surface if it was perfectly evenly distributed and there were no cracks - it can take almost anything. But glass also has rather weak tensile strength. There’s always tiny hairline fractures in glass, and imagine what happens when you pull apart a piece of glass where there’s a crack - the crack just spreads and the pane comes apart.
When you try to bend a pane of glass, one side gets compressed (the side that’s being folded over) and the other side gets stretched. The compressed side has no problem whatsoever, but if the stretched (tensile stress) side gets stretched too far, it breaks along the hairline cracks.
“Toughened” or “tempered” glass (which Prince Rupert’s drops are) are a clever way to get around this; they have internal compression stress, pressure wanting to explode. In the case of panes of chemically toughened soda lime glass, they first make the glass, then they soak it in molten potassium salts, so the sodium in the glass is replaced by larger potassium ions, so that when the glass cools it’s stressed. With thermally toughened (tempered) glass, like Prince Rupert’s drops, the glass cools much faster on the outside than on the inside, so it becomes a fixed size, and then when the inside cools, it pulls on the outside from the inside.
You’d think that internal stress would be bad, but it’s just the opposite. Because glass can take compressive force like a beast, the extra compressive stress is meaningless. But when you try to put tensile stress on the glass, it first has to overcome its internal compression. So there’s no actual tension on the hairline fractures.
In short, Prince Rupert drops are bulletproof because they work by the same principle as bulletproof glass. Bulletproof glass usually also has layers of plastic (laminated glass) holding multiple panes together, but the basic principle is the same.
Cool picture here:
You can see the stress patterns inside the glass when viewed through a polarization filter.
I wonder what it would do if hit by a .223 or .308, that would be interesting.
The strength isn’t infinite - eventually, if you deliver enough energy in as small of a space as possible in as short of a period of time as possible, you’ll break it. But tempered glass is amazingly strong.
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