Page 66 - The Miracle in the Spider

66 THE MIRACLE IN THE SPIDER

verybody knows that spiders use silky threads produced from
their own bodies in order to spin webs. But the stages of
E production of the thread and its general features are not so well
known. The thread produced by spiders, of a diameter less than one
thousandth of a millimetre, is five times stronger than a steel thread of the
same dimensions. It can, moreover, stretch to four times its own length.
Another striking feature of the silk is that it is very light. We can
demonstrate this with an example. A silk thread stretching around the
whole world would only weigh 320 grams. 20
It will be worth having another look at the above technical details.
We cannot just gloss over the fact that the silk is five times stronger than
steel. Because steel, known for being one of the strongest materials in the
world, is an alloy produced in large factories in a series of processes.
Spiders' silk, however, five times stronger than steel, is not produced in
large factories: it is made by an arachnid. Just about any spider we can see
anywhere can produce it. Steel is a heavy material, for which reason it is
difficult to use. It is produced in large furnaces at high temperatures and
is prepared for use by cooling in moulds. In contrast, spiders' thread is
very light. It is produced in the spiders' own small bodies, not in giant
furnaces and moulds.
Another miraculous aspect of spider thread is that it is very elastic.
It is very difficult to find a material both strong and elastic. For example,
steel cables are one of the strongest materials around. But because they are
not elastic like rubber, they slowly lose their shape. And although rubber
cables do not lose their shape, they are not strong enough to lift heavy
weights. On the other hand, as has been described above, spider silk is
five times stronger than steel wire of the same thickness, and 30 percent
more elastic than rubber of the same thickness. 21 To put it in technical
terms, spider thread, from the point of view of its resistance to breaking
and the extent it can stretch before breaking, is a material the like of which
does not exist.
The research into spiders carried out over the last few decades, and
the information resulting from it, has brought with it several questions.