Ultracentrifugation is a laboratory technique used to separate components of a mixture based on their density. It involves spinning samples at very high speeds in a centrifuge, which generates strong centrifugal forces. This process causes denser particles to move towards the bottom of the container, while lighter components remain closer to the top. This method is commonly used in biochemistry and molecular biology to isolate proteins, nucleic acids, and cell organelles. By adjusting the speed and duration of the centrifugation, researchers can effectively separate and analyze different components for various scientific applications.