How Does a Plant Become a T-Shirt?

Step 1 of 5

The fluff is for the seeds.

The cotton plant makes a pod, and inside, each seed grows a coat of long fine hairs. When the pod bursts, the fluff catches the wind and carries the seeds away from the parent plant.

Step 2 of 5

Every fibre is a flattened tube.

Under a microscope a cotton hair is a hollow tube that has collapsed and twisted like a ribbon. Those natural twists are what let the fibres grip each other when they are spun.

Step 3 of 5

Twisting is what makes it strong.

A handful of loose fibres pulls apart at once. Twist them and each one squeezes on its neighbours, so pulling the thread only tightens the grip — the same trick as in a rope.

Step 4 of 5

Weaving is just over and under.

Cloth is threads laid out one way with more threads passed over and under them at right angles. That simple crossing is what stops the whole thing pulling apart in any direction.

Step 5 of 5

It breathes because it is hollow.

Those collapsed tubes soak up sweat and let air through, which is why cotton is comfortable in heat. It is also why it stays wet for a long time once it is soaked.

Cotton is a thirsty crop. Growing enough for one T-shirt can take a couple of thousand litres of water.