Talk:Ninja rocks

message: I'd like to see someone with some knowledge on the subject add a section to this entry explaining the physics behind how porcelain shards are able to silently break glass. Alvis 08:31, 19 February 2006 (UTC)
replies: text: That would be good, but none of the sources I've found go into the mechanics. Melchoir 01:01, 20 February 2006 (UTC)
replies: text: I'd just came to the talk page to ask the exact some thing... hmmm... well I probably am the one here with a degree in physics.... Mathmo 00:54, 16 April 2006 (UTC)

text: I see this is now an editorial concern. The East County News reported on a demonstration they witnessed by police: the burglar throws a handful of ninja rocks moderately hard against a car window, and they bounce off with a quiet rattling noise. The window is intact but has microscopic fractures. He then gently pushes the window in with a gloved hand. Since Wikipedia is not an instruction manual, I don't think we need to give the method in detail, but rest assured that it works. Melchoir 05:51, 24 July 2006 (UTC)

text: And this is just out in left field. One of those newspaper articles even had a picture in it. What were you expecting, a peer-reviewed journal article in Nature just to prove that the California Assembly and Supreme Court know what they're doing? There is no reliable source that justifies writing "some may identify as fear mongering"; it's your personal opinion, it's original research, it's unverified, and it has no place in a Wikipedia article. Melchoir 05:37, 30 July 2006 (UTC)

text: Okay, but seriously, what more evidence can you ask for than a demonstration of the technique performed by police in front of journalists and photographers? If that doesn't back up the claims with physical evidence, what does? Melchoir 06:51, 30 July 2006 (UTC)
thread_title:  Physics 

message: I saw Ninja rocks on a television program once, they explained that it is because the glass has a negative or positive charge (can't remember which) and the ceramic has the opposite charge, so when forced together they react to each other and something has to give, which is the glass as its weaker than the ceramic.
Perhaps someone can do some research based on this information.
Kurt wills 14:57, 3 May 2007 (UTC)
replies: text: Neither glass nor ceramics have any overall charge Dav2008 22:57, 18 May 2007 (UTC)
thread_title:  Possible explanation 

message: I'm really surprised this issue of how they work in practice was brought up over a year ago and still no one has simply tested it and been able to report back.  Just go to a junkyard or abandoned building or somewhere you can break glass without much trouble and test the things out, then we'll know.  —Preceding unsigned comment added by 149.31.44.113 (talk) 19:33, 1 October 2007 (UTC)
replies: text: By the way, I just found this video which shows them being used and working.  Reading the comments on the video are also interesting as many of them assert that they've seen it happen before as well.  There is one comment which claims the video is a fake, but most do not believe it to be so and give reports of it being used in a number of instances before.  —Preceding unsigned comment added by 149.31.44.113 (talk) 19:46, 1 October 2007 (UTC)
thread_title: Testing of ninja rocks?

message: Hello there, unregistered member helping you out. I dislike editing actual articles, so one of you guys could do it?
THIS is the thing. At least open it so you understand what I'm saying. Glass is 6,5 and porcelain is somewhere between 5 and 6. So it's almost as hard as glass. Iron is 4, weaker than porcelain and even WEAKER than glass. Think about that! It's strange, but once you get it, it's simple. If you hit a window with a hammer, chances are it will break, but if you don't hit hard enough, it won't break. Trust me I've tried. If you hit it with porcelain, it's much more likely to shatter. If you hit it with a DIAMOND, then it will break VERY EASILY. Read the article I linked for info.
For example, the hardest element with a 10 on the mohs hardness scale (diamond) is 4 times harder than an element that measures 9 (corundum); whereas a 4 on the scale is only about 10% harder than a 3. Since the Mohs' hardness scale is a relative scale and not an absolute scale, the numbers assigned to each element should be used for reference purposes only. Remember we are talking about porcelain, not clay here.
Car breakers use this because if you fail to break the window with a hammer it will make a very loud bang. You can't risk that. If the porcelain isn't thrown hard enough it just chips off making almost no sound at all. 
--91.154.52.137 (talk) 20:32, 27 June 2008 (UTC)
replies: text: "Remember we are talking about porcelain" Wrong. Spark plugs are made from alumina ceramic; a very different material to porcelain and one which is not harder and stronger than both porcelain and glass.  —Preceding unsigned comment added by 203.160.114.205 (talk) 23:29, 31 October 2008 (UTC)
thread_title:  Want proof? Here. 

message: I wrote this article:
http://www.ridelust.com/obscure-burglary-tools-of-the-day-ninja-rocks/
which is where the line "Tempered glass used in automobile windows is softer on the Mohs scale than spark plug ceramic (specifically aluminum oxide ceramic). Aluminum oxide ceramic rates a 9 on the Mohs scale; diamonds are 10, glass is 6.5." came from.  
The only references I used for that article were when I wikied the actual Mohs hardnesses of those particular materials.  I wrote the rest from personal and professional knowledge.  I would appreciate it if someone cited that line.  Thank you.  —Preceding unsigned comment added by 108.2.17.230 (talk) 13:44, 26 June 2010 (UTC)
thread_title:  Uncredited lines 

message: I recently rewrote the lead section to better explain the concept to someone unfamiliar with the subject, so if nobody has any problem with it then I am going to remove the maintenance tag at the top of the page. Orchastrattor (talk) 13:12, 20 May 2021 (UTC)
thread_title:  Clarity maintenance tag