A cotton gin is a machine that separates cotton fibers from their seeds. Before this invention, workers had to remove seeds by hand, a slow and tedious process. One person working all day could clean only about a pound of cotton.

In 1793, Eli Whitney invented a cotton gin that could clean much more cotton per day than a person working by hand. The machine used a rotating cylinder with wire hooks to pull the cotton fibers through small slots, too narrow for the seeds to pass through. The seeds fell away while the clean fibers came out the other side.

This invention transformed American agriculture and industry. Cotton became much cheaper to process, making cotton cloth more affordable for many people. Factories could now get enough cotton to weave into fabric on a massive scale. The cotton gin turned cotton into one of America's most valuable crops and helped expand the Industrial Revolution.

While the cotton gin was an important technological achievement, it had devastating consequences too: it made cotton farming so profitable that it increased the demand for enslaved labor in the South, deepening and extending the brutal system of slavery in the United States.