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What Makes Spider Webs Tough As Steel

samzenpus posted more than 2 years ago | from the it's-all-how-you-spin-it dept.

Science 76

sciencehabit writes "A new analysis reveals the intricacies of spider web design, showing how the unique properties of its silk turn webs into flexible yet strong traps. Computer simulations reveal that heavy forces spread over the entire net rather than stay local. Real spider silk can be either stretchy or stiff at different times, which produces threads that flex and then snap in just the right way to avoid wrecking nearby spokes."

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76 comments

I for one (0, Insightful)

Anonymous Coward | more than 2 years ago | (#38899741)

welcome our new genetically-created-giant-super-spiders-to-make-building-material-for-us-but-then-fought-back overlords.

Re:I for one (0, Offtopic)

Anonymous Coward | more than 2 years ago | (#38899861)

Well crap. I wish I knew I was going to be first post. I might have tried to say something Insightful instead instead of falling back to a standard /. meme. I should have known that the first time I ever post first I'd end up wasting it, and not even on purpose like everyone else!

Let this be your lesson. With great power comes great responsibility.

(dang, I fell back to a standard spiderman reference. I'm bad at this)

Re:I for one (4, Interesting)

Securityemo (1407943) | more than 2 years ago | (#38899901)

You apparently can use spider silk for cloth if you really try hard enough [wired.com]. (Warning: NSF arachnophobes.)

Re:I for one (1)

hannson (1369413) | more than 2 years ago | (#38901697)

Here's something I'm sure some of you'll find interesting: http://www.ted.com/talks/cheryl_hayashi_the_magnificence_of_spider_silk.html

I know! (-1)

Anonymous Coward | more than 2 years ago | (#38899751)

It's frosty piss. Followed up by a foot-long deuce.

Diamond (3, Funny)

Anonymous Coward | more than 2 years ago | (#38899873)

I think all this research is just skirting around the "real" material engineering question: What makes diamonds the hardest metal?

Re:Diamond (5, Funny)

Anonymous Coward | more than 2 years ago | (#38899953)

... the hardest metal?

/facepalm

Re:Diamond (3, Funny)

Anonymous Coward | more than 2 years ago | (#38901187)

Okay, okay -- if you're going to be that picky: One of the hardest metals.

Re:Diamond (0)

Anonymous Coward | more than 2 years ago | (#38903739)

... the hardest metal?

/facepalm

lol. I take it you're not up to snuff on your memes.

http://knowyourmeme.com/memes/diamond-the-hardest-metal

Re:Diamond (0)

Anonymous Coward | more than 2 years ago | (#38904159)

I take it you're not up to snuff on your memes.

Being popular on 4chan doesn't make it a meme.

Re:Diamond (1)

ghn (2469034) | more than 2 years ago | (#38899961)

Diamonds are made of carbon and carbon is not metal. But yes they are hard.

Re:Diamond (5, Funny)

Anonymous Coward | more than 2 years ago | (#38900285)

chemistry is hard

Re:Diamond (2)

CSMoran (1577071) | more than 2 years ago | (#38900751)

Diamonds are made of carbon and carbon is not metal under usual conditions.

FTFY

Re:Diamond (3, Informative)

silentcoder (1241496) | more than 2 years ago | (#38901253)

>Diamonds are made of carbon and carbon is not metal under usual conditions.

Metals are a specific set of elements. They have a specific set of properties caused by the way their atoms combine with themselves and each other. This allows them to form unique types of compounds we call "alloys", to be highly effective energy conductors (notably electricity and heat), and causes them to shine (yes, being shiny is an attribute of metals). Many other substances (both elements and compounds) share some of these attributes under certain conditions (for example - glass is shiny) but only metals have them all because the combination derives from the unique lattice structures that metal atoms form.

In essence metals are those elements that don't form molecules at all (at least, not the way anything else does). Metals arrange their nuclei in intricate lattices with electrons flowing through these and capable of passing from one atom to the next. All those macroscopic identifiable properties I mentioned are caused by this structure. When metals combine with each other they merge their lattices and form alloys rather than compounds. When metals combine with non-metals they form "traditional" molecular compounds (Sodium is a metal, Chlorine is not - when they combine they don't form an alloy they form salt).
Another attribute of metals is that because of their electron structure they are always reactive to acids and all acid+metal reactions have the same result. The hydrogen in the acid gets replaced with the metal, releasing the hydrogren as a gas and forming a salt.

So erm... under what possible conditions can carbon ever change it's atomic structure and chemical behavior to become a metal ? Short of nuclear transmutation - in which case the result is NOT carbon.

Please, do explain as I would love to know.

Re:Diamond (0)

Anonymous Coward | more than 2 years ago | (#38901385)

Damn. I wish I had this clear explanation at the chemistry lessons back when I was at school.

Re:Diamond (0)

Anonymous Coward | more than 2 years ago | (#38903013)

It is impossible to explain chemistry like this to a whole class. You have to teach to the bottom of the class. If you want to achieve a 85 average like they tell you to get, and if you want your students to rate you high like they tell you to get, then you mostly have to teach to the bottom of the class. You can't teach those kids (mostly kids, most people taking basic chemistry are going to be less then 21), anything about how chemistry works. You can't teach them to understand what they are doing. What you can teach them is how to earn partial credit on test questions and how to get credit for lab reports without cheating.

I can't say anything about high school level chemistry, but if you are talking about university level chemistry, your professor and or Teaching Assistant would have been happy to give you a better one-on-one or one-on-few explanation outside of class hours. This is one reason they have "Office Hours". Office hours are primarily used by the less intelligent but hard working students, as regularly going to office hours can make a C student a B student or a B student an A student. The D and F students don't typically go to office hours and they often don't even hand in assignments. That's why they are D and F students. However, a student could go to office hours just to talk with the TA and try to get a deeper understanding of the material. As long as they don't try to due this right before an exam or some other busy time, the TA will have time to explain chemistry to an inquisitive student.

Long story short, if you didn't learn chemistry very well in university, it was your own fault, the faculty and TA's would have explained it better if you had asked. You can't expect them to try to teach you well during normal class hours because then the dumb students wouldn't even figure out how to get partial credit.

Re:Diamond (5, Informative)

CSMoran (1577071) | more than 2 years ago | (#38901471)

So erm... under what possible conditions can carbon ever change it's atomic structure and chemical behavior to become a metal ? Short of nuclear transmutation - in which case the result is NOT carbon. Please, do explain as I would love to know.

Sure thing.

First, let's go beyond your high-school level description of what a metal is. There is no "specific set of elements" that are metallic. Rather, a metal is something that, owing to delocalized electrons, has no band gap at the Fermi level and thus is a good conductor of electricity and heat. This can be achieved in many elements, not necessarily those that are typically thought of as metals, by using fancy conditions, such as extreme pressures and/or temperatures.

Take, for instance, this report on metallic carbon in Phys. Rev. Lett: http://prl.aps.org/abstract/PRL/v102/i5/e055703 [aps.org]
or the infamous metallic hydrogen, http://lt26.iphy.ac.cn/abstract/pdf/B1488.pdf [iphy.ac.cn]

Re:Diamond (1)

alex67500 (1609333) | more than 2 years ago | (#38902287)

I like /. when I can learn something. It's been often recently, but I think you've just about made up for it.
Thanks!

Only on slashdot! (2)

mcgrew (92797) | more than 2 years ago | (#38902613)

Will you have a serious discussion of chemistry, metalurgy, and physics in response to a joke! And maybe even learn something.

Re:Diamond (0)

Anonymous Coward | more than 2 years ago | (#38903903)

Likewise, electronic band gap theory tells us that 1/3 of all possible single-walled carbon nanotubes are metallic, while 2/3 are semiconducting. Intrinsic graphene is a zero-gap semiconductor, multi-walled carbon nanotubes are generally metallic. There are numerous papers directly or indirectly relating to attempts to engineer the band gap of these materials. Basically, if you can control the bandgap of a material, you can control its electronic and optical properties.

http://en.wikipedia.org/wiki/Carbon_nanotube#Electrical_properties
http://en.wikipedia.org/wiki/Carbon_nanotube#Multi-walled
http://en.wikipedia.org/wiki/Graphene#Electronic_properties

Re:Diamond (2)

decsnake (6658) | more than 2 years ago | (#38902731)

hmm... I'm not a chemist, but last time I checked steel (an alloy of iron and carbon) was a metal, which seems to contradict pretty much all of what you wrote.

Re:Diamond (4, Informative)

sadness203 (1539377) | more than 2 years ago | (#38899975)

They already know that.... And there's other stuff harder than diamond too. Wurtzite boron nitride and the mineral lonsdaleite come to mind.

Re:Diamond (5, Funny)

Yaotzin (827566) | more than 2 years ago | (#38900007)

I always thought Dragonforce was the hardest metal known to man.

Re:Diamond (0)

Anonymous Coward | more than 2 years ago | (#38900925)

no match for this
http://www.cleverkit.com/product_images/g/nokia_3410__54102.jpg

Source of the diamond=metal meme (1)

Anonymous Coward | more than 2 years ago | (#38900297)

FYI:
http://img86.imageshack.us/img86/2429/1146987213907xw5.jpg

Re:Diamond (1)

Saintwolf (1224524) | more than 2 years ago | (#38901181)

What makes diamonds the hardest metal?

1. Diamonds are made from carbon, a non-metal. 2. They are hard because the atoms are perfectly linked in a lattice shape Did you not go to High School?

Spiders have always fascinated me (4, Interesting)

Tastecicles (1153671) | more than 2 years ago | (#38899883)

I've lost count of the number of times I've sat there and just watched a spider start building a web at 4am, finishing at around 10, and just marvelling at the insane complexity and beauty of the thing.

Re:Spiders have always fascinated me (1, Interesting)

DigiShaman (671371) | more than 2 years ago | (#38899931)

I was driving home on a major interstate at 4am when a fat-n-juicy spider decided to repel down my rear view mirror. Freaked me the hell out! Jerking the steering wheel only made matters worse when it caused the spider to sway back and fourth. I eventually lost track of it and was nervous driving the rest of the way home. Never can tell when or where it will make its next grand apperience.

Re:Spiders have always fascinated me (1)

Ogive17 (691899) | more than 2 years ago | (#38902381)

I had a similar experience, my reaction was to swat at it with my right hand. I swung so hard that I knocked my rear view mirror off the windshield.. oddly enough I felt no pain in my hand.

The spider landed on the passenger seat and then scurried under it. I was paranoid the rest of the ride home.

Re:Spiders have always fascinated me (1)

Anonymous Coward | more than 2 years ago | (#38902919)

Plotting. Planning. It was deciding on how it could crawl up your ass unnoticed. Maybe bite your nutsack on the way up for extra points.

Re:Spiders have always fascinated me (1)

cyberchondriac (456626) | more than 2 years ago | (#38905129)

Dunno what you guys were so unnerved about, unless it was a black widow or a brown recluse. ..or maybe something huge and gross like a wolf spider - which are pretty cool, actually. Personally, it's cockroaches that skeeve me out. And crickets, for some odd reason.

Cheryl Hayashi at Ted Talk (4, Informative)

Anonymous Coward | more than 2 years ago | (#38900071)

http://www.ted.com/talks/cheryl_hayashi_the_magnificence_of_spider_silk.html

Radioactive spiders? (1)

Nyder (754090) | more than 2 years ago | (#38900073)

Really surprised no one has thrown a Spider-man comment.

Re:Radioactive spiders? (1)

EdIII (1114411) | more than 2 years ago | (#38900393)

Really surprised no one has thrown a Spider-man comment.

Probably because it would have only been some crude comment about how hard it was to milk Spider-man. Slashdot is better than that right?

Re:Radioactive spiders? (1)

netwarerip (2221204) | more than 2 years ago | (#38901741)

Really surprised no one has thrown a Spider-man comment.

Probably because it would have only been some crude comment about how hard it was to milk Spider-man. Slashdot is better than that right?

Seriously? The dude lives with his aunt and hasn't gotten any from Mary Jane in years. Would take about 8 seconds, the Sears catalog lingerie section, and a spoonful of baby oil.

Re:Radioactive spiders? (0)

Anonymous Coward | more than 2 years ago | (#38902781)

He'd better be careful how he bends his fingers or that could end up being very... sticky.

Re:Radioactive spiders? (1)

lwriemen (763666) | more than 2 years ago | (#38901749)

Especially since the findings in the article only reveal what the Spider-Man comics have been telling us for years.

spider silk can be either stretchy or stiff at different times, which produces threads that flex and then snap in just the right way

...usually to help Spider-Man catch the bad guy or avoid a fatal situation, natch!

Smack yourself with steel and then a spider web (2)

mtm_king (99722) | more than 2 years ago | (#38900083)

I call bullshit on the heading "Spider Webs Tough As Steel". I have hit my head on spider webs and on steel. I am absolutely sure that spider webs are not anywhere near as tough as steel. Thank you, good night.

Re:Smack yourself with steel and then a spider web (3, Insightful)

geminidomino (614729) | more than 2 years ago | (#38900435)

When was the last time you "hit your head" on a thread of steel 0.15mm in diameter?

Re:Smack yourself with steel and then a spider web (3, Funny)

mtm_king (99722) | more than 2 years ago | (#38900469)

Good point. But back at you.... When is the last time you "hit your head" on a 1/4 inch plate of spider web.

Re:Smack yourself with steel and then a spider web (0)

Anonymous Coward | more than 2 years ago | (#38901673)

Well, that's that. No more sleeping for me. Ever.

Re:Smack yourself with steel and then a spider web (0)

Anonymous Coward | more than 2 years ago | (#38902741)

Just the other day actually. But once I caught sight of the spider I stopped caring about how tough the web was.

Re:Smack yourself with steel and then a spider web (4, Informative)

Zinho (17895) | more than 2 years ago | (#38906359)

You're confusing hardness, strength, and toughness; it's easy to do, considering that laymen use these terms loosely and interchangeably. The researchers in the article were almost certainly using the technical definitions, which are roughly as follows:

Hardness is a measure of how well a material resists deformation. Typical hardness tests involve things like seeing what it will scratch/what scratches it (Mohs [wikipedia.org] scale) or how deeply a probe will dent it under a given load (Rockwell [wikipedia.org] scale). It's used as an indication of wear resistance, and steels used for cutting tools or stamping dies often have high hardness.

Strength is a measure of how much stress (force divided by cross sectional area) is required to permanently deform (yield [wikipedia.org] strength) or break (ultimate [wikipedia.org] strength) a sample of the material. Strength is widely used in engineering design to make sure there is enough material (cross sectional area) to safely handle a given load (force).

Toughness is the energy required to break a sample of the material. This can be found by integrating the area under the stress/strain curve of a tensile test (work = force x distance) or measured directly with purpose-built tools (Izod [wikipedia.org] or Charpy [wikipedia.org] impact test).

Hardness is correlated with strength, and can be used as a non-destructive estimate of strength for finished parts. In contrast, the toughness of samples with the same strength will vary depending on the brittleness of the samples. Ductile samples will stretch a large amount (high strain) before failing and so will have higher toughness than brittle materials of equal strength which won't stretch as far (low strain) before failing.

Given those definitions it's easy to see that even if spider silk had lower strength than steel it could easily have the same or higher toughness if it can stretch far enough. Since spider silk is actually comparable in strength [wikipedia.org] to premium steels and has much better elongation before failure (stretches to 4x original length) I'd expect its toughness to be much higher than steel.

Which I'd rather be smacked in the head with is an entirely different question, that has to to with suitability as a weapon. The steel bar is likely to be denser (therefore heavier) and stiffer than a same-size block of spider silk, so it would probably do more damage to my head at equal speeds. I don't know how the spider silk would do for hardness in bulk, but with better toughness it would likely take more of a beating while keeping its original shape; on the other hand a well-used steel pipe would probably work better as a threat than a new-looking spider silk baton. On the gripping hand, a blackjack [wikipedia.org] made with spider silk would be pretty cool, and I definitely wouldn't want to get hit with one. Pick your poison, I guess.

Skin? (5, Informative)

aaronb1138 (2035478) | more than 2 years ago | (#38900223)

Not to deny the amazing properties of spider silk, but the article mentions, "In fact, such self-sacrificing by a unit is highly unusual among natural materials, Buehler notes."

I find this highly inconsistent with biology in general. In the human body, one such system we call skin. As a specific example, callouses are groupings of skin cells which die and harden to protect areas of the hands and feet frequently engaged by stresses, such as shoes and using hand tools (normally skin sloughs off). Continuing just with skin, note the way that even when cleaved, skin puts significant friction against the object cleaving (watch a piercing in slow motion some time). To overcome this, physicians are taught to cut along skin grains, which also reduces scarring.

Other sacrificial organic materials, well tree bark is frequently harder than the material inside. Hair on various animals prevents predators from getting a firm grip. Salamander tails come off once a tension threshold is crossed. Cell membranes flex, usually right up to the point contents would be damaged by the intrusion anyway. Cell walls work like bricks, giving plants firm structure, and making them difficult if not impossible to slice up for electron microscopy (not sure if that barrier has been crossed). Trees and plants lose branches in the wind and tumbleweed completely detaches from its roots. Fruit has skins just strong enough to prevent spoiling several days before being eaten by animals, thus spreading seeds. Seeds and nuts have cleavage lines to make them strong, but allow the bud to break out.

There are many other examples, but functional, purpose built tissues and substances in organic materials are very common.

Re:Skin? (0)

Anonymous Coward | more than 2 years ago | (#38904113)

nuts have cleavage

Ummm, that's on a different part of the other gender's body. Just sayin is all...

Re:Skin? Context is important. (2)

b4dc0d3r (1268512) | more than 2 years ago | (#38904831)

"Natural materials" and "tissues and organic materials" seem to be different things. Going by dictionary meanings might lead you in one direction, but the context of the quote suggests Ferris was not talking about "anything [natural] made of matter."

I wouldn't consider a salamander tail to be a "natural material", nor would I consider skin nor cells nor plants as a whole. You could maybe make an argument for bark and hemp fiber, but I think that still qualifies as "highly unusual among natural materials."

Molecular dynamics, not FEA? (1)

lancelet (898272) | more than 2 years ago | (#38900605)

Having read the paper, I wonder: why did they choose to do their calculations using molecular dynamics software and not a finite element package? I could be reading it wrong, but their approach seems to have been to implement a cable-element FEA inside the molecular dynamics software... Struck me as kind-of like using a spreadsheet for image manipulation; maybe it's what you're familiar with, but it sure isn't the easiest route.

What Makes Spider Webs Tough As Steel (2, Funny)

Anonymous Coward | more than 2 years ago | (#38900617)

Spiders.

Next!

what (0)

Anonymous Coward | more than 2 years ago | (#38900771)

What Makes Spider Webs Tough As Steel

I dunno. Yo mama?

Stretchy or Stiff (0)

Anonymous Coward | more than 2 years ago | (#38900901)

Real spider silk can be either stretchy or stiff at different times,

- Just like my penis. Perhaps I have hidden spider-powers.

Oh look... (1)

RussellSHarris (1385323) | more than 2 years ago | (#38901643)

Someone is fascinated by the way a fabric of structural elements in tension behave. It's almost cute.

In all seriousness, though, TFA was pretty light on the details. It sounds like a really interesting simulation, but a dumbed-down write-up is just kinda ... well, almost too watered down to be very interesting.

Re:Oh look... (1)

b4dc0d3r (1268512) | more than 2 years ago | (#38905081)

I'm not sure Daniel Strain is reading, you might want to comment on the article directly, or send Daniel a message on how to improve as an author, as well as choosing more interesting topics to write about.

Re:Oh look... (0)

Anonymous Coward | more than 2 years ago | (#38906459)

Since you already took the trouble to post that, why don't you?

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