Spider silk is pretty darn strong and all sorts of comparisons are made to steel. I'm more curious about the various moduli of spider silk and how it compares to other materials. What is the Young's modulus of spider silk? What is the bulk modulus of spider silk? What is the shear modulus of spider silk? In general how do those moduli describe the material properties of spider.

A simpler way to ask the question, what does it mean when it is said that spider silk is strong?

  • $\begingroup$ I do recall that (at least some) spiders produce two variants of silk, one sticky and one not - the latter being used in construction of the web. $\endgroup$
    – Rory M
    Feb 28, 2012 at 19:35

1 Answer 1


Wikipedia has a remarkably well-cited article on the subject of silks and their various biological isoforms and mechanical properties. With respect to tensile strength, spider's silk is as tough as high-grade steel.

Explcitly, dragline silk was measured by Pérez-Rigueiro at al. to be 600 ± 50 MPa with a comparison to silkworm silk.


  • $\begingroup$ I hate to admit that wikipedia does pretty much answer this question. Followup question. What does it mean? $\endgroup$
    – bobthejoe
    Feb 28, 2012 at 23:02
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    $\begingroup$ You can think of tensile strength as how much pressure you need to exert pulling along the long axis before causing failure in the material, and it snapping. Pressure here means force applied over surface area of the face, or cross-section, of the material, with SI units of 10^6 Pascals, or MPa. $\endgroup$
    – user560
    Feb 28, 2012 at 23:07
  • $\begingroup$ I do also hate to refer people to Wikipedia in most cases, but they do a good job of the fundamentals. Who knew it was such a hot research topic. $\endgroup$
    – user560
    Feb 28, 2012 at 23:09
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    $\begingroup$ Why is everyone so down on wikipedia, even though everyone uses it?? As a jumping off point for research into a topic you are unfamiliar with, it is excellent. Once you know more, you can then cite the appropriate original papers and will be able to sift the good from the bad (and downright ugly). $\endgroup$
    – Poshpaws
    Feb 29, 2012 at 12:47
  • $\begingroup$ Poshpaws I completely agree, and that's why I thought it was suitable in this case to refer to the Wikipedia page. There are many pages there however that are poorly cited and even though the information may be accurate, many people take what is documented as factual and authoritative. It is an invaluable tool to explore areas with which you have little familiarity. $\endgroup$
    – user560
    Feb 29, 2012 at 18:38

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