Spider silk is one of the strongest fibers and toughest materials found in nature, – it’s even stronger than steel
Spider silk is made up of chains of amino acids, proteins called fibroins. It’s very strong – in fact, weight for weight it’s tougher than steel – yet also extremely elastic. These two characteristics, together, make for one unique substance in nature that the world’s greatest material scientists have been trying to re-create artificially.
When compared with a piece of steel the same diameter, spider silk is five times stronger than steel. It has also been hypothesised that a pencil-width of spider silk held up in front of a Boeing 747, would be enough to stop it in flight! Although, obviously, this hasn’t been tested.
In comparison to Kevlar, which is the strongest man-made polymer, spider silk is almost as strong – but not quite. Which is still extremely impressive for a little creature that lives in your back garden.
Silk is secreted as a liquid from the spider by the spinnerets, which are special glands located in the tip of the arachnid’s abdomen. Upon contact with air the liquid instantly hardens to become a fine but strong silk. As the material is produced, the spider pulls it into long, thin threads using its legs.
The reason the spider itself does not become caught in its own web is that, first, it knows which sticky strands to avoid and, second, the adhesive hardens if the unwitting victim makes a sudden movement, but not with the gentle, considered movements of the spider.
Photograph: Scott Anderson
Image from www.flickr.com/photos/stuutje