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Twist turns short fibres into long ones

How Does Fluff Become Thread?

Twisting short fibres squeezes them against each other, and the friction makes them behave as one long strand.

1 A puff of loosefibres2 Twistedtogether3 One long strand
No fibre runs the whole length. Twist is what makes it hold.
  1. Step 1 of 5

    Cotton and wool fibres are only centimetres long.

    A cotton fibreabout 2-3 cmA wool fibreabout 5-10 cmThe thread they makeas long as youlike

    There is no fibre in your shirt running from hem to collar. Every one of them is a few centimetres at most.

  2. Step 2 of 5

    Twisting presses them together.

    A finished thread Fibres spiralling andsqueezing inward

    Spinning wraps the fibres around each other in a spiral. That spiral squeezes inward, pinning every fibre against its neighbours.

  3. Step 3 of 5

    Friction does the actual holding.

    A thread under tensionFriction gripping every fibreYour pull trying to slide them apart

    Pull on the thread and each fibre is gripped along its whole length by the ones around it. Nothing is glued or knotted — it is all friction.

  4. Step 4 of 5

    More twist is stronger, up to a point.

    Barely twistedpulls apart inthe handWell twistedstrong andflexibleOver-twistedkinks up andbreaks

    Add twist and the squeeze tightens. Add far too much and the fibres are wound so hard that they start to snap instead.

  5. Step 5 of 5

    Weaving does the same trick again, bigger.

    One thread Fibres held by twistWoven cloth Threads held bycrossings

    Threads laid over and under each other lock at every crossing. The cloth holds together for exactly the reason the thread does.

    Spun thread turns up in the archaeological record around 34,000 years ago — twisted flax fibres from a cave in Georgia, dyed in several colours.

The short version

Thread is short fibres twisted until they squeeze against each other hard enough that friction holds them as one long strand.

Try it yourself

Pull a thread from an old cloth and untwist it between your fingers. It falls into a useless puff of short fibres.

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