• New 'Mechanical Metamaterial' Expands When You Compress It, Shrinks When You Stretch It
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[QUOTE][TABLE="width: 700"] [TR] [TD][TABLE="width: 500"] [TR] [TD]Metamaterials research has generally focused on media with strange or unique electromagnetic properties, like the ability to bend light or sound in an unnatural way, but materials scientists at Northwestern University are experimenting with an [URL="http://www.newscientist.com/article/dn21839-impossible-material-would-stretch-when-compressed.html"]entirely new kind of material[/URL] with unique mechanical properties. A team there has designed materials with “negative compressibility” that in theory will compress when they are pulled and expand when they are compressed. In other words, sit on a cushion and it pushes back against the force of your weight. This sounds counterintuitive, of course, but their design makes some kind of sense. One would expect that any material that behaves this way would be, by definition, unstable--and therefore would collapse into a stable state on its own, thus nullifying whatever characteristics the unstable state possessed. But the Northwestern team designed around this by creating an internal structure that does indeed fall into a stable state. The stable state is just more compressed or expanded than the original state. That’s confusing, so we’re going to borrow from [URL="http://www.newscientist.com/article/dn21839-impossible-material-would-stretch-when-compressed.html"]New Scientist's[/URL] explanation (click through for some more thorough visuals). Think of a row of four horizontal particles making up a material that inherently wants to expand. Each is made up of molecules that attract one another to certain and unequal degrees, and that attraction keeps the material from expanding.The inner two particles share a weak attraction that can be broken when the material is stretched. But when the bond between the inner particles is broken, the outer particles respond by attracting each other even more, creating compression that counters the stretching. But compressing the material brings the two inner particles back together again, re-establishing the weak bond and allowing the material to resume expanding. It’s confusing, but in theory it could work. Someday such materials could be used to coat the outside of military vehicles or shelters to push back against an incoming blast.[/TD] [/TR] [/TABLE] [/TD] [TD][TABLE="width: 500"] [TR] [TD][IMG]http://www.popsci.com/files/imagecache/article_image_large/articles/MemoryFoam-fast.jpeg[/IMG] [SUB][SUP][B]Mechanical Metamaterials Could Create Cushions That Push Back[/B][/SUP][/SUB][/TD] [/TR] [/TABLE] [/TD] [/TR] [/TABLE] [QUOTE][tab]Source: [/tab][URL="http://www.popsci.com/technology/article/2012-05/new-mechanical-metamaterial-expands-when-you-compress-it-shrinks-when-you-stretch-it"]Popular Science[/URL][/QUOTE][/QUOTE] In the future, we can create rocks that looks like cushions.
Wait... So... You press it, it grows, thus the force of your press becomes higher, which causes it to expand even further. Science is so goddamn cool, but so goddamn confusing sometimes.
''In other words, sit on a cushion and it pushes back against the force of your weight'' What.
Flubber. The NBA is going to get a lot more exciting.
[QUOTE=farmatyr;36067654]In the future, we can create rocks that looks like cushions.[/QUOTE] Pillow-fights suddenly become a lot more deadly
[QUOTE=Scottismelol;36067686]''In other words, sit on a cushion and it pushes back against the force of your weight'' What.[/QUOTE] Isn't that what like, most solid (and non solid) things do? I assume this is different because it expands, further than it's original volume, with pressure that should shrink it.
What happens if you push two objects made of this material against each other in an enclosed space?
[QUOTE=Agent Cobra;36067711]Pillow-fights suddenly become a lot more deadly[/QUOTE] [IMG]http://facepunch.com/members/2860-Agent-Cobra[/IMG] Imagine what this could mean for military armors? Vests that don't drag the soldier down because of ceramic plates. Diving suits that double as armor? Everyday clothing that deflects small arms fire? I dunno.
[QUOTE=maurits150;36067759]What happens if you push two objects made of this material against each other in an enclosed space?[/QUOTE] Same thing as when you increase pressure on gas in a container I'd imagine, pressure increases and either the piston pushing can't push anymore, or the container breaks (or temperature becomes so high it catches fire/explodes). [editline]23rd May 2012[/editline] [QUOTE=sHiBaN;36067768][IMG]http://facepunch.com/members/2860-Agent-Cobra[/IMG] Imagine what this could mean for military armors? Vests that don't drag the soldier down because of ceramic plates. Diving suits that double as armor? Everyday clothing that deflects small arms fire? I dunno.[/QUOTE] I'd imagine there is a limit to how much it can push back with (also because bullets have a very high force on a very small area, it would probably just pierce it).
This can be done at home with corn starch and water, just mix it up until you can't move your spoon fast through the mixture, but you should be able to move it slowly. This makes a mixture that you can punch it, and it won't splatter, it actually turns solid under pressure. However if you gently move your fingers through it, it's like water. Check out this video I made with the same substance. [video=youtube;qzfKty4k1Zk]http://www.youtube.com/watch?v=qzfKty4k1Zk[/video]
That is actually super creepy. Thank you for sharing.
[quote]Metamaterials research has generally focused on media with strange or unique electromagnetic properties, like the ability to bend light or sound in an unnatural way[/quote] [quote]electromagnetic properties[/quote] [quote]sound[/quote]
[QUOTE=bluesky;36067808]This can be done at home with corn starch and water, just mix it up until you can't move your spoon fast through the mixture, but you should be able to move it slowly. This makes a mixture that you can punch it, and it won't splatter, it actually turns solid under pressure. However if you gently move your fingers through it, it's like water. Check out this video I made with the same substance. Video[/QUOTE] That's a non-newtonian fluid though, I doubt it's the same concept as this thing attempts to expand its volume when force is applied unlike that, which just hardens. Further this was with a steady, continuous force and not a soundwave or similar.
[QUOTE=bluesky;36067808]This can be done at home with corn starch and water, just mix it up until you can't move your spoon fast through the mixture, but you should be able to move it slowly. This makes a mixture that you can punch it, and it won't splatter, it actually turns solid under pressure. However if you gently move your fingers through it, it's like water. Check out this video I made with the same substance. [video=youtube;qzfKty4k1Zk]http://www.youtube.com/watch?v=qzfKty4k1Zk[/video][/QUOTE] that's not the same thing at all that's just a non-newtonian fluid
This has been around for years. Chinese finger traps.
I call shennaningans.
So is it like memory foam 2.0?
Obligatory: My penis has had this technology for decades. [editline]23rd May 2012[/editline] [QUOTE=markg06;36068519]So is it like memory foam 2.0?[/QUOTE] I think the image is stock. I don't imagine it shares too much in common with memory foam.
Everything you know is wrong.
Wait what. Where does the potential energy come from? I'm pretty sure the news article is just very misleading.
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