When people in India first started to grow cotton, they picked the seeds out by hand before they spun the cotton into thread. By 500 BC, women in India used a rolling pin to get the seeds out of cotton. There’s a picture of one in the Ajanta Caves. In the Middle Ages women used an improved version that you rolled with your feet.
Then about 1100 AD, Indian scientists invented a machine with gears to turn rollers. This machine, the churka, got the seeds out of the cotton more quickly and easily. Over time, people improved this machine. First they added foot pedals. Later they used water power, using the current of a fast stream to turn the rollers.
When white people first started to grow cotton in North America in the 1600s AD, they brought over cotton churkas from India to help them get the seeds out. In the 1700s AD, farmers in the southern part of North America started to grow more and more cotton. Along the Atlantic coast, farmers could grow long-staple cotton. The long fibers worked in the Indian cotton churka.
Cotton farmers, who were mostly white, forced African people to work as slaves and pick the cotton seeds out by hand. Mostly land-owners made enslaved African-Americans pick cotton seeds out in the evenings, after they’d already worked all day in the fields picking the cotton. This was too slow, and it made cotton very expensive – so expensive that nobody wanted to make clothes out of it.
Clearly you could make clothes much more cheaply if only you could get the seeds out of the cotton, especially with the new spinning and weaving machines that had just been invented in England. A lot of people began to work on inventing a new kind of churka that would get the seeds out of short-staple cotton. Finally in 1793, just after the Revolutionary War, a young white man named Eli Whitney did invent a cotton gin that worked. The cotton gin was a lot like the old churka, but it had steel teeth that caught the cotton fibers, and a system of pulleys to pull harder.
Cotton farmers all used the new cotton gin. Between the cotton gin and the spinning and weaving machines, cotton clothing got so cheap that many people began to wear cotton instead of linen. Clothes got a lot cheaper, so that for the first time in history most people had more than one outfit to wear. People even started to wear underwear!
The bad part was that in order to plant and pick so much cotton, the cotton farmers brought over thousands and thousands more African people to be their slaves and work in the cotton fields. Most of the African people who came to North America and to Brazil as slaves came because of the cotton gin.
Learn by doing: a project with cotton
More about cotton
Or more about American clothing
More about United States slavery