Talk:Prince Rupert's drop

Untitled
The 18 January 2006 edit had (incorrectly) switched tensile and compressive stresses in the explanation of how these drops work. The compressive stress on the surface is what causes the strengthening effect; glass, like all brittle materials, is far stronger in compression than in tension, which means that it will generally fail from tensile stress, especially when subject to both kinds of stress (e.g. bending). If the surface was in tension, it's likely that the glass would fracture spontaneously.

Czar's Tears?
I can find no confirmation of this phrase anywhere in Google Books, Google News Archive, or Google Scholar (and I tried "Tsar's tears" as well). It may be that this is a translation of a (Russian?) name, but if so we should indicate e.g.
 * or Слезы царя. (lit. Czar's tears)

If we cannot source this should be deleted as Wikipedia is now the "only source". --Dhartung | Talk 07:19, 18 February 2008 (UTC)

Changing the title of this page
Will someone who knows more about Wikipedia editing than I do, please change the name of this entry. No one ever talks about Prince Rupert's Drops in the singular. The page should be named: Prince Rupert's Drops. Not Prince Rupert's Drop. Alwyn Eades (talk) 20:40, 7 April 2010 (UTC)
 * The naming policy WP:SINGULAR, states that the singular is used. Although people would always collectively call dogs dogs, the article is Dog. Same thing with these drops. ( Hohum  @ ) 21:27, 7 April 2010 (UTC)

Fair enough, but I think that the singular rule is inappropriately applied in this case. I have worked with many scientists on Prince Rupert’s Drops and heard them talk on hundreds of occasions. I have never heard any of them say “Prince Rupert’s Drop” in the singular. To me and to people in the field “Prince Rupert’s Drops” is not the plural of a “Prince Rupert’s Drop” but is the name of a phenomenon called “Prince Rupert’s Drops”.

So just as Wikipedia has (correctly) entries like “Systems theory”, “Law of sines”, “Linguistics” and “Milankovitch cycles”, it should have an entry “Prince Rupert’s Drops”.(Alwyn Eades (talk) 20:04, 9 June 2010 (UTC))


 * I agree, the title should be "Prince Rupert's Drops". None of the multiple references in the article refer to the phenomena or artifacts in the singular, and the current article title reads as a bizarre Wikipedia linguistic affectation. Since there is ample precedent for escaping this Procrustean bed, let's establish a consensus and get the title fixed.   Reify-tech (talk) 18:28, 29 March 2013 (UTC)

Prince Rupert's Drop Gun ?
Is it possible to build a gun like this ? The drop is tightly fit in the breech. When the firing pin hits and drop is exploded the ball rushes out and do the usual gun thing ? Jon Ascton   (talk)  05:07, 12 August 2010 (UTC)

This might work, but you would probably get more oomph from the spring used to break the tail, since making a good impedance match between the shattered glass bits and your notional projectile is not easy. This is why firearms (and piston engines) work so well - the hot expanding gases couple most of their energy to the piston or projectile as it accelerates in time. Getting a disintegrating solid to couple to another solid doesn't work nearly as well. — Preceding unsigned comment added by 129.55.200.20 (talk) 18:16, 20 November 2012 (UTC)

kudos
the introductory paragraph is actually written by someone who knows how to write; I can't say that of any other article I've seen on Wikipedia, although I've probably seen thousands. 84.153.200.162 (talk) 16:11, 12 August 2010 (UTC)

Damage
This fracture velocity, while fast in human terms, is only about Mach 0.3 to Mach 0.5 in the glass itself (Vs ~4,000m/sec). One way to view a Rupert's drop is as a stretched rubber band. The glass is extremely elastic and the strain energy, when released, allows the inner regions of the glass to recoil outwards towards the surface, propelling them over a large distance. A simple classroom demonstration of this is to shoot a rubber band across the room - the recoil of the stretched rubber is what propels it away from the point of release. A Rupert's drop is like zillions of little glass rubber bands all stretched toward the center of the drop. When the tail is broken, these stretched glass shards then shoot outwards in all directions. — Preceding unsigned comment added by 129.55.200.20 (talk) 18:09, 20 November 2012 (UTC)

Crack front propagation speed?
The article claims "2300 – 3000 metres per second", the source "1450-1900 m/s". Which one is more correct? --Michael Schumacher (talk) 19:33, 16 July 2013 (UTC)


 * I'm sure the guys who imaged them will know. Of course, it will depend on the kind of glass; they differ a lot in density for example, and you would guess the maximum crack speed it close to the speed of sound which depends on density.  For now I've edited out what is not in the brief abstract referenced.  A fuller report from them on their glass would be useful but for now we cannot write down a Mach number in the solid.  There's not a lot of value in my view of a comparison solid crack speeds with the velocity of sound in air, for sound always propagates faster in solids. Oops, forgot to sign this.TSRL (talk) 21:56, 1 August 2014 (UTC)

not sure how this could be correct
"Because of their use as a party piece, Prince Rupert’s Drops became widely known in the late 17th century — far more than today. It can be seen that educated people (or those in “society”) were expected to be familiar with them"

wouldn't peoples familiarity with them make them poor party pieces? If a group of people were expected to know how a certain magic trick works then you would get no reaction from that group thus making it a poor choice of trick.

Magicalbendini (talk) 19:54, 1 August 2014 (UTC)

DM: "400-year-old secret of the Prince Rupert's drop solved: Scientists say stress and tension is behind their 'superstrength'"
For someone (else) to add to the main article: http://www.dailymail.co.uk/sciencetech/article-4489980/400-year-old-secret-Prince-Rupert-s-drop-solved.html Phantom in ca (talk) 03:44, 10 May 2017 (UTC)


 * ✅ done, but used the original article from phys.org rather than the one from The Mail. Thanks for the heads up. Richerman    (talk) 10:48, 16 May 2017 (UTC)

The slower glass cools, the denser it ends up
I've always believed ("known"?) that the reason Prince Rupert's Drops are so robust is as follows:


 * 1) The slower glass cools, the more dense the final solid is
 * 2) When a blob of glass is dropped into water, the surface cools and solidifies rapidly, while the interior is still liquid
 * 3) As the interior slowly cools and solidifies it continues to shrink, putting the interior under extreme tension and, consequently, the surface under extreme compression

I was surprised to see nothing of this effect in this article; it just states that the inside is under tension and the outside is under compression, but not how that came about. It would be great to add this info, but I'm not sure how to back it up (especially since, confusingly, the article just released by Science Magazine at http://www.sciencemag.org/news/2017/05/video-why-hammer-won-t-break-unusual-piece-glass claimed that scientists only now understand them).

Here's a reference article on how cooling rates affect glass, including its density: http://www.eg.bucknell.edu/~kvollmay/JCP105_4714_1996.pdf

-- Dan Griscom (talk) 21:39, 16 May 2017 (UTC)

Inconsistent capitalization
Is it "Prince Rupert's Drops," or "Prince Rupert's drops"? The article uses both capital and lowercase D, seemingly randomly. Or is there some grammar rule I don't know about? — Preceding unsigned comment added by 108.56.192.85 (talk) 18:35, 9 May 2018 (UTC)

Some plagiarism in the Scientific section
I think the author needs to adjust some paragraphs. There is some plagiarism, copied directly from the reference in the section discussing new findings.

https://phys.org/news/2017-05-scientists-year-old-mystery-prince-rupert.amp CelesteRaynolds1 (talk) 17:11, 1 January 2023 (UTC)