Silk fabric is soft and fine.
Silk fabric is made into fine clothes.
Threads spun by silkworms is woven to make the fabric.
Silkworms are caterpillars, not worms. They are the larvae of the silk moth.
The life cycle of the silk moth
The silk moth female mates with a male moth and then lays about 300 eggs. The larvae hatch from the eggs and eat mulberry leaves. They eat and grow, and about every five days they moult. This means that their old skins split and fall off, revealing a larger, new skin underneath. After about 45 days, the silkworm is ready to become a pupa. It stops eating and spins a cocoon made from a single thread of silk. Inside the cocoons, the silkworms change into a moth and cut their way out of the cocoon. The moths mate and the cycle begins again.
A silk moth. Jupiter Images
Silkworms eat only mulberry leaves ©iStock
On silk farms, silkworms are kept on trays and fed leaves from mulberry bushes which are grown especially to feed them.
Mulberry leaves are the only leaves the silkworms eat.
Silkworms spin cocoons
When the silkworms are ready to spin their cocoons, they are put into cane frames. They attach themselves to the cane and spin their cocoons. Each cocoon is made from one long, continuous thread, and that is the reason that the thread can be used to make fabric.
© iStock
In a silk farm, the silkworms attach to bamboo canes and spin cocoons ©iStock
Coccons are soaked in hot water and then the threads are unwound.
iStock
Processing the silk threads
Most of the cocoons are taken to a steam room where the pupae die inside the cocoons. The cocoons are soaked in hot water to soften the sticky gum that holds the threads together. Each cocoon is brushed to find the end of the single thread. The threads of eight cocoons are unwound at the same time by reeling machines. The eight threads are twisted together to form one silk thread.
The threads are dyed. The dyed threads are twisted (plied) together into thicker, stronger threads and then woven into cloth.
In the factory, some of the cocoons are allowed to develop into moths so that they will mate and lay eggs to produce more silk worms. But the threads of most of the cocoons are used to make silk.
Uses of silk
Silk is used to make clothing, ribbon, lace, scarves and ties. Bed sheets and cushions are also made using silk.
Silk threads going into the weaving machines at a silk factory. Getty Images
Did you know?
Once silk was used to make parachutes, bicycle tyres, and bulletproof vests! Now these things are made of nylon and other artificial materials.
Silk is a fine, delicate fabric. Getty images
The properties of silk
It is a lightweight fabric which makes light and comfortable clothing that is warm in winter and cool in summer.
It is the strongest natural fibre.
It can be dyed in many colours.
Silk has been around for thousands of years. Silk was made in ancient China. Today China, as well as Thailand, India and Japan, have thriving silk industries and sell their silk to countries around the world.