An ultracentrifuge is a laboratory instrument that spins samples at very high speeds, generating strong centrifugal forces. This allows scientists to separate components of a mixture based on their density. Common applications include separating cellular components, such as organelles, and purifying proteins or nucleic acids. The device typically consists of a rotor that holds the samples and can reach speeds of over 100,000 revolutions per minute (RPM). Ultracentrifuges are essential in fields like biochemistry, molecular biology, and clinical research, enabling researchers to analyze and isolate specific substances for further study.